text:
VSEPR theory
From Wikipedia, the free encyclopedia
Jump to: navigation, search
Example of bent electron arrangement. Shows location of unpaired electrons, bonded atoms, and bond angles. (Water molecule) The bond angle for water is 104.5°.
Valence shell electron pair repulsion (VSEPR) theory is a model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms.[1] It is also named the Gillespie-Nyholm theory after its two main developers. The acronym "VSEPR" is pronounced either "ves-pur"[2]:410 or "vuh-seh-per".[3]
The premise of VSEPR is that the valence electron pairs surrounding an atom tend to repel each other and will, therefore, adopt an arrangement that minimizes this repulsion, thus determining the molecule's geometry. Gillespie has emphasized that the electron-electron repulsion due to the Pauli exclusion principle is more important in determining molecular geometry than the electrostatic repulsion.[4]
VSEPR theory is based on observable electron density rather than mathematical wave functions and hence unrelated to orbital hybridisation,[5] although both address molecular shape. While it is mainly qualitative, VSEPR has a quantitative basis in quantum chemical topology (QCT) methods such as the electron localization function and the quantum theory of atoms in molecules (QTAIM).[4]
Contents
[hide]
1 History
2 Overview
3 Degree of repulsion
4 AXE method
5 Examples
6 Exceptions
6.1 Some AX2E0 molecules
6.2 Some AX2E2 molecules
6.3 Some AX6E1 and AX8E1 molecules
7 Transition metal molecules
8 Odd-electron molecules
9 See also
10 References
11 Further reading
12 External links
History[edit]
The idea of a correlation between molecular geometry and number of valence electrons (both shared and unshared) was originally proposed in 1939 by Ryutaro Tsuchida in Japan,[6] and was independently presented in a Bakerian Lecture in 1940 by Nevil Sidgwick and Herbert Powell of the University of Oxford.[7] In 1957, Ronald Gillespie and Ronald Sydney Nyholm of University College London refined this concept into a more detailed theory, capable of choosing between various alternative geometries.[8][9]
Overview[edit]
VSEPR theory is used to predict the arrangement of electron pairs around non-hydrogen atoms in molecules, especially simple and symmetric molecules, where these key, central atoms participate in bonding to two or more other atoms; the geometry of these key atoms and their non-bonding electron pairs in turn determine the geometry of the larger whole.
The number of electron pairs in the valence shell of a central atom is determined after drawing the Lewis structure of the molecule, and expanding it to show all bonding groups and lone pairs of electrons.[2]:410–417 In VSEPR theory, a double bond or triple bond are treated as a single bonding group.[2] The sum of the number of atoms bonded to a central atom and the number of lone pairs formed by its nonbonding valence electrons is known as the central atom's steric number.
The electron pairs (or groups if multiple bonds are present) are assumed to lie on the surface of a sphere centered on the central atom and tend to occupy positions that minimize their mutual repulsions by maximizing the distance between them.[2]:410–417[10] The number of electron pairs (or groups), therefore, determines the overall geometry that they will adopt. For example, when there are two electron pairs surrounding the central atom, their mutual repulsion is minimal when they lie at opposite poles of the sphere. Therefore, the central atom is predicted to adopt a linear geometry. If there are 3 electron pairs surrounding the central atom, their repulsion is minimized by placing them at the vertices of an equilateral triangle centered on the atom. Therefore, the predicted geometry is trigonal. Likewise, for 4 electron pairs, the optimal arrangement is tetrahedral.[2]:410–417
Degree of repulsion[edit]
The overall geometry is further refined by distinguishing between bonding and nonbonding electron pairs. The bonding electron pair shared in a sigma bond with an adjacent atom lies further from the central atom than a nonbonding (lone) pair of that atom, which is held close to its positively charged nucleus. VSEPR theory therefore views repulsion by the lone pair to be greater than the repulsion by a bonding pair. As such, when a molecule has 2 interactions with different degrees of repulsion, VSEPR theory predicts the structure where lone pairs occupy positions that allow them to experience less repulsion. Lone pair–lone pair (lp–lp) repulsions are considered stronger than lone pair–bonding pair (lp–bp) repulsions, which in turn are considered stronger than bonding pair–bonding pair (bp–bp) repulsions, distinctions that then guide decisions about overall geometry when 2 or more non-equivalent positions are possible.[2]:410–417 For instance, when 5 valence electron pairs surround a central atom, they adopt a trigonal bipyramidal molecular geometry with two collinear axial positions and three equatorial positions. An electron pair in an axial position has three close equatorial neighbors only 90° away and a fourth much farther at 180°, while an equatorial electron pair has only two adjacent pairs at 90° and two at 120°. The repulsion from the close neighbors at 90° is more important, so that the axial positions experience more repulsion than the equatorial positions; hence, when there are lone pairs, they tend to occupy equatorial positions as shown in the diagrams of the next section for steric number five.[10]
The difference between lone pairs and bonding pairs may also be used to rationalize deviations from idealized geometries. For example, the H2O molecule has four electron pairs in its valence shell: two lone pairs and two bond pairs. The four electron pairs are spread so as to point roughly towards the apices of a tetrahedron. However, the bond angle between the two O–H bonds is only 104.5°, rather than the 109.5° of a regular tetrahedron, because the two lone pairs (whose density or probability envelopes lie closer to the oxygen nucleus) exert a greater mutual repulsion than the two bond pairs.[2]:410–417[10]
An advanced-level explanation replaces the above distinction with two rules:
Bent's rule: An electron pair of a more electropositive ligand constitutes greater repulsion. This explains why the Cl in PClF4 prefers the equatorial position and why the bond angle in oxygen difluoride (103.8°) is smaller than that of water (104.5°). Lone pairs are then considered to be a special case of this rule, held by a "ghost ligand" in the limit of electropositivity.
A higher bond order constitutes greater repulsion. This explains why in phosgene, the oxygen–chlorine bond angle (124.1°) is larger than the chlorine–chlorine bond angle (111.8°) even though chlorine is more electropositive than oxygen. In the carbonate ion, all three bond angles are equivalent due to resonance.
AXE method[edit]
The "AXE method" of electron counting is commonly used when applying the VSEPR theory. The A represents the central atom and always has an implied subscript one. The X represents each of ligands (atoms bonded to A). The E represents the number of lone electron pairs surrounding the central atom.[2]:410–417 The sum of X and E is known as the steric number.
Based on the steric number and distribution of Xs and Es, VSEPR theory makes the predictions in the following tables. Note that the geometries are named according to the atomic positions only and not the electron arrangement. For example, the description of AX2E1 as a bent molecule means that the three atoms AX2 are not in one straight line, although the lone pair helps to determine the geometry.
Steric
number
Molecular geometry[11]
0 lone pairs
Molecular geometry[2]:413–414
1 lone pair
Molecular geometry[2]:413–414
2 lone pairs
Molecular geometry[2]:413–414
3 lone pairs
2

Linear (CO2)
3

Trigonal planar (BCl3)
V-shape (SO2)
4

Tetrahedral (CH4)
Trigonal pyramidal (NH3)
Bent (H2O)
5

Trigonal bipyramidal (PCl5)
Seesaw (SF4)
T-shaped (ClF3)
Linear (I−
3)
6

Octahedral (SF6)
Square pyramidal (BrF5)
Square planar (XeF4)
7

Pentagonal bipyramidal (IF7)[10]
Pentagonal pyramidal (XeOF−
5)[12]
Pentagonal planar (XeF−
5)[13]:498
8

Square antiprismatic
(TaF3−
8)[10]
9
Tricapped trigonal prismatic (ReH2−
9)[13]:254
or
Capped square antiprismatic[citation needed]
10
Bicapped square antiprismatic
or
Bicapped dodecadeltahedral[14]:1165,1721
11
Octadecahedral[14]:1165,1721
12
Icosahedral[14]:1165,1721
14
Bicapped hexagonal antiprismatic[14]:1165,1721
Molecule
type
Shape[2]:413–414
Electron arrangement[2]:413–414
including lone pairs, shown in pale yellow
Geometry[2]:413–414
excluding lone pairs
Examples
AX2E0
Linear BeCl2,[1] HgCl2,[1] CO2[10]
AX2E1
Bent NO−
2,[1] SO2,[2]:413–414 O3,[1] CCl2
AX2E2
Bent H2O,[2]:413–414 OF2[13]:448
AX2E3
Linear XeF2,[2]:413–414 I−
3,[13]:483 XeCl2
AX3E0
Trigonal planar BF3,[2]:413–414 CO2−
3,[13]:368 NO−
3,[1] SO3[10]
AX3E1
Trigonal pyramidal NH3,[2]:413–414 PCl3[13]:407
AX3E2
T-shaped ClF3,[2]:413–414 BrF3[13]:481
AX4E0
Tetrahedral CH4,[2]:413–414 PO3−
4, SO2−
4,[10] ClO−
4,[1] XeO4[13]:499
AX4E1
Seesaw or disphenoidal SF4[2]:413–414[13]:45
AX4E2
Square planar XeF4[2]:413–414
AX5E0
Trigonal bipyramidal PCl5[2]:413–414
AX5E1
Square pyramidal ClF5,[13]:481 BrF5,[2]:413–414 XeOF4[10]
AX5E2
Pentagonal planar XeF−
5[13]:498
AX6E0
Octahedral SF6,[2]:413–414 WCl6[13]:659
AX6E1
Pentagonal pyramidal XeOF−
5,[12] IOF2−
5[12]
AX7E0
Pentagonal bipyramidal[10] IF7[10]
AX8E0
Square antiprismatic[10] IF−
8, ZrF4−
8, ReF−
8
AX9E0
Tricapped trigonal prismatic (as drawn)
or
capped square antiprismatic ReH2−
9[13]:254
When the substituent (X) atoms are not all the same, the geometry is still approximately valid, but the bond angles may be slightly different from the ones where all the outside atoms are the same. For example, the double-bond carbons in alkenes like C2H4 are AX3E0, but the bond angles are not all exactly 120°. Likewise, SOCl2 is AX3E1, but because the X substituents are not identical, the X–A–X angles are not all equal.
As a tool in predicting the geometry adopted with a given number of electron pairs, an often used physical demonstration of the principle of minimal electron pair repulsion utilizes inflated balloons. Through handling, balloons acquire a slight surface electrostatic charge that results in the adoption of roughly the same geometries when they are tied together at their stems as the corresponding number of electron pairs. For example, five balloons tied together adopt the trigonal bipyramidal geometry, just as do the five bonding pairs of a PCl5 molecule (AX5) or the two bonding and three non-bonding pairs of a XeF2 molecule (AX2E3). The molecular geometry of the former is also trigonal bipyramidal, whereas that of the latter is linear.
Examples[edit]
The methane molecule (CH4) is tetrahedral because there are four pairs of electrons. The four hydrogen atoms are positioned at the vertices of a tetrahedron, and the bond angle is cos−1(− 1⁄3) ≈ 109° 28′.[15][16] This is referred to as an AX4 type of molecule. As mentioned above, A represents the central atom and X represents an outer atom.[2]:410–417
The ammonia molecule (NH3) has three pairs of electrons involved in bonding, but there is a lone pair of electrons on the nitrogen atom.[2]:392–393 It is not bonded with another atom; however, it influences the overall shape through repulsions. As in methane above, there are four regions of electron density. Therefore, the overall orientation of the regions of electron density is tetrahedral. On the other hand, there are only three outer atoms. This is referred to as an AX3E type molecule because the lone pair is represented by an E.[2]:410–417 By definition, the molecular shape or geometry describes the geometric arrangement of the atomic nuclei only, which is trigonal-pyramidal for NH3.[2]:410–417
Steric numbers of 7 or greater are possible, but are less common. The steric number of 7 occurs in iodine heptafluoride (IF7); the base geometry for a steric number of 7 is pentagonal bipyramidal.[10] The most common geometry for a steric number of 8 is a square antiprismatic geometry.[14]:1165 Examples of this include the octacyanomolybdate (Mo(CN)4−
8) and octafluorozirconate (ZrF4−
8) anions.[14]:1165
The nonahydridorhenate ion (ReH2−
9) in potassium nonahydridorhenate is a rare example of a compound with a steric number of 9, which has a tricapped trigonal prismatic geometry.[13]:254[14] Another example is the octafluoroxenate ion (XeF2−
8) in nitrosonium octafluoroxenate(VI),[13]:498[17][18] although in this case one of the electron pairs is a lone pair, and therefore the molecule actually has a distorted square antiprismatic geometry.
Possible geometries for steric numbers of 10, 11, 12, or 14 are bicapped square antiprismatic (or bicapped dodecadeltahedral), octadecahedral, icosahedral, and bicapped hexagonal antiprismatic, respectively. No compounds with steric numbers this high involving monodentate ligands exist, and those involving multidentate ligands can often be analysed more simply as complexes with lower steric numbers when some multidentate ligands are treated as a unit.[14]:1165,1721
Exceptions[edit]
There are groups of compounds where VSEPR fails to predict the correct geometry.
Some AX2E0 molecules[edit]
The gas phase structures of the triatomic halides of the heavier members of group 2, (i.e., calcium, strontium and barium halides, MX2), are not linear as predicted but are bent, (approximate X–M–X angles: CaF2, 145°; SrF2, 120°; BaF2, 108°; SrCl2, 130°; BaCl2, 115°; BaBr2, 115°; BaI2, 105°).[19] It has been proposed by Gillespie that this is caused by interaction of the ligands with the electron core of the metal atom, polarising it so that the inner shell is not spherically symmetric, thus influencing the molecular geometry.[20][21] Ab initio calculations have been cited to propose that contributions from d orbitals in the shell below the valence shell are responsible.[22] Disilynes are also bent, despite having no lone pairs.[23]
Some AX2E2 molecules[edit]
One example of the AX2E2 geometry is molecular lithium oxide, Li2O, a linear rather than bent structure, which is ascribed to its bonds being essentially ionic and the strong lithium-lithium repulsion that results.[24] Another example is O(SiH3)2 with an Si–O–Si angle of 144.1°, which compares to the angles in Cl2O (110.9°), (CH3)2O (111.7°), and N(CH3)3 (110.9°).[20] Gillespie and Robinson rationalize the Si–O–Si bond angle based on the observed ability of a ligand's lone pair to most greatly repel other electron pairs when the ligand electronegativity is greater than or equal to that of the central atom.[20] In O(SiH3)2, the central atom is more electronegative, and the lone pairs are less localized and more weakly repulsive. The larger Si–O–Si bond angle results from this and strong ligand-ligand repulsion by the relatively large -SiH3 ligand.[20] Burford et al showed through X-ray diffraction studies that Cl3Al–O–PCl3 has a linear Al–O–P bond angle and is therefore a non-VSEPR molecule.[citation needed]
Some AX6E1 and AX8E1 molecules[edit]
Xenon hexafluoride, which has a distorted octahedral geometry.
Some AX6E1 molecules, e.g. xenon hexafluoride (XeF6) and the Te(IV) and Bi(III) anions, TeCl2−
6, TeBr2−
6, BiCl3−
6, BiBr3−
6 and BiI3−
6, are octahedra, rather than pentagonal pyramids, and the lone pair does not affect the geometry to the degree predicted by VSEPR.[25] One rationalization is that steric crowding of the ligands allows little or no room for the non-bonding lone pair;[20] another rationalization is the inert pair effect.[13]:214
Transition metal molecules[edit]
Hexamethyltungsten, a transition metal compound whose geometry is different from main group coordination.
Many transition metal compounds have unusual geometries, which can be ascribed to ligand bonding interaction with the d subshell and to absence of valence shell lone pairs.[26] Gillespie suggested that this interaction can be weak or strong. Weak interaction is dealt with by the Kepert model, while strong interaction produces bonding pairs that also occupy the respective antipodal points of the sphere.[4] This is similar to predictions based on sd hybrid orbitals[27][28] using the VALBOND theory. The repulsion of these bidirectional bonding pairs leads to a different prediction of shapes.
Molecule type
Shape
Geometry
Examples
AX2
Bent VO+
2
AX3
Trigonal pyramidal CrO3
AX4
Tetrahedral TiCl4[13]:598–599
AX5
Square pyramidal Ta(CH3)5[29]
AX6
Trigonal prismatic W(CH3)6[30]
The square planar shape associated with a d8 electronic configuration is an exception to the Kepert model. This can be rationalized by considering the increased crystal field stabilization energy as compared to a tetrahedral geometry.
Odd-electron molecules[edit]
The VSEPR theory can be extended to molecules with an odd number of electrons by treating the unpaired electron as a "half electron pair" — for example, Gillespie and Nyholm[8]:364–365 suggested that the decrease in the bond angle in the series NO+
2 (180°), NO2 (134°), NO−
2 (115°) indicates that a given set of bonding electron pairs exert a weaker repulsion on a single non-bonding electron than on a pair of non-bonding electrons. In effect, they considered nitrogen dioxide as an AX2E0.5 molecule, with a geometry intermediate between NO+
2 and NO−
2. Similarly, chlorine dioxide (ClO2) is an AX2E1.5 molecule, with a geometry intermediate between ClO+
2 and ClO−
2.[citation needed]
Finally, the methyl radical (CH3) is predicted to be trigonal pyramidal like the methyl anion (CH−
3), but with a larger bond angle (as in the trigonal planar methyl cation (CH+
3)). However, in this case, the VSEPR prediction is not quite true, as CH3 is actually planar, although its distortion to a pyramidal geometry requires very little energy.[31]
See also[edit]
Bent's rule (effect of ligand electronegativity)
Linear combination of atomic orbitals
Molecular geometry
Molecular modelling
Software for molecular modeling
Thomson problem
Valency interaction formula
References[edit]
^ Jump up to: a b c d e f g Jolly, W. L. (1984). Modern Inorganic Chemistry. McGraw-Hill. pp. 77–90. ISBN 0-07-032760-2.
^ Jump up to: a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad Petrucci, R. H.; W. S., Harwood; F. G., Herring (2002). General Chemistry: Principles and Modern Applications (8th ed.). Prentice-Hall. ISBN 0-13-014329-4.
Jump up ^ Stoker, H. Stephen (2009). General, Organic, and Biological Chemistry. Cengage Learning. p. 119. ISBN 978-0-547-15281-3.
^ Jump up to: a b c Gillespie, R. J. (2008). "Fifty years of the VSEPR model". Coord. Chem. Rev. 252: 1315–1327. doi:10.1016/j.ccr.2007.07.007.
Jump up ^ Gillespie, R. J. (2004), "Teaching molecular geometry with the VSEPR model", J. Chem. Ed., 81 (3): 298–304, Bibcode:2004JChEd..81..298G, doi:10.1021/ed081p298
Jump up ^ Tsuchida, Ryutarō (1939). 新簡易原子價論 [New simple valency theory]. J. Chem. Soc. Jpn. (in Japanese). 60 (3): 245–256. doi:10.1246/nikkashi1921.60.245.
Jump up ^ Sidgwick, N. V.; Powell, H. M. (1940). "Bakerian Lecture. Stereochemical Types and Valency Groups". Proc. Roy. Soc. A. 176: 153–180. Bibcode:1940RSPSA.176..153S. doi:10.1098/rspa.1940.0084.
^ Jump up to: a b Gillespie, R. J.; Nyholm, R. S. (1957). "Inorganic stereochemistry". Quart. Rev. Chem. Soc. 11: 339. doi:10.1039/QR9571100339.
Jump up ^ Gillespie, R. J. (1970). "The electron-pair repulsion model for molecular geometry". J. Chem. Educ. 47 (1): 18. Bibcode:1970JChEd..47...18G. doi:10.1021/ed047p18.
^ Jump up to: a b c d e f g h i j k l m Miessler, G. L.; Tarr, D. A. (1999). Inorganic Chemistry (2nd ed.). Prentice-Hall. pp. 54–62. ISBN 0-13-841891-8.
Jump up ^ Petrucci, R. H.; W. S., Harwood; F. G., Herring (2002). General Chemistry: Principles and Modern Applications (8th ed.). Prentice-Hall. pp. 413–414 (Table 11.1). ISBN 0-13-014329-4.
^ Jump up to: a b c Baran, E. (2000). "Mean amplitudes of vibration of the pentagonal pyramidal XeOF−
5 and IOF2−
5 anions". J. Fluorine Chem. 101: 61–63. doi:10.1016/S0022-1139(99)00194-3.
^ Jump up to: a b c d e f g h i j k l m n o p q Housecroft, C. E.; Sharpe, A. G. (2005). Inorganic Chemistry (2nd ed.). Pearson. ISBN 978-0-130-39913-7.
^ Jump up to: a b c d e f g h Wiberg, E.; Holleman, A. F. (2001). Inorganic Chemistry. Academic Press. ISBN 0-12-352651-5.
Jump up ^ Brittin, W. E. (1945). "Valence Angle of the Tetrahedral Carbon Atom". J. Chem. Educ. 22 (3): 145. Bibcode:1945JChEd..22..145B. doi:10.1021/ed022p145.
Jump up ^ "Angle Between 2 Legs of a Tetrahedron" – Maze5.net
Jump up ^ Peterson, W.; Holloway, H.; Coyle, A.; Williams, M. (Sep 1971). "Antiprismatic Coordination about Xenon: the Structure of Nitrosonium Octafluoroxenate(VI)". Science. 173 (4003): 1238–1239. Bibcode:1971Sci...173.1238P. ISSN 0036-8075. PMID 17775218. doi:10.1126/science.173.4003.1238.
Jump up ^ Hanson, Robert M. (1995). Molecular origami: precision scale models from paper. University Science Books. ISBN 0-935702-30-X.
Jump up ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0-08-037941-9.
^ Jump up to: a b c d e Gillespie, R. J.; Robinson, E. A. (2005). "Models of molecular geometry". Chem. Soc. Rev. 34: 396–407. doi:10.1039/b405359c.
Jump up ^ Bytheway, I.; Gillespie, R. J.; Tang, T. H.; Bader, R.F (1995). "Core Distortions and Geometries of the Difluorides and Dihydrides of Ca, Sr, and Ba". Inorg. Chem. 34 (9): 2407–2414. doi:10.1021/ic00113a023.
Jump up ^ Seijo, Luis; Barandiarán, Zoila; Huzinaga, Sigeru (1991). "Ab initio model potential study of the equilibrium geometry of alkaline earth dihalides: MX2 (M=Mg, Ca, Sr, Ba; X=F, Cl, Br, I)". J. Chem. Phys. 94 (5): 3762. Bibcode:1991JChPh..94.3762S. doi:10.1063/1.459748.
Jump up ^ Sekiguchi, Akira; Kinjō, Rei; Ichinohe, Masaaki (September 2004). "A Stable Compound Containing a Silicon–Silicon Triple Bond" (PDF). Science. 305 (5691): 1755–1757. Bibcode:2004Sci...305.1755S. PMID 15375262. doi:10.1126/science.1102209.
Jump up ^ Bellert, D.; Breckenridge, W. H. (2001). "A spectroscopic determination of the bond length of the LiOLi molecule: Strong ionic bonding". J. Chem. Phys. 114: 2871. Bibcode:2001JChPh.114.2871B. doi:10.1063/1.1349424.
Jump up ^ Wells, A. F. (1984). Structural Inorganic Chemistry (5th ed.). Oxford Science Publications. ISBN 0-19-855370-6.
Jump up ^ Kaupp, Martin (2001). ""Non-VSEPR" Structures and Bonding in d0 Systems". Angew. Chem. Int. Ed. Engl. 40 (1): 3534–3565. doi:10.1002/1521-3773(20011001)40:19<3534::AID-ANIE3534>3.0.CO;2-#.
Jump up ^ Landis, C. R.; Cleveland, T.; Firman, T. K. (1995). "Making sense of the shapes of simple metal hydrides". J. Am. Chem. Soc. 117: 1859–1860. doi:10.1021/ja00111a036.
Jump up ^ Landis, C. R.; Cleveland, T.; Firman, T. K. (1996). "Structure of W(CH3)6". Science. 272: 179–183. doi:10.1126/science.272.5259.179f.
Jump up ^ King, R. Bruce (2000). "Atomic orbitals, symmetry, and coordination polyhedra". Coord. Chem. Rev. 197: 141–168. doi:10.1016/s0010-8545(99)00226-x.
Jump up ^ Haalan, A.; Hammel, A.; Rydpal, K.; Volden, H. V. (1990). "The coordination geometry of gaseous hexamethyltungsten is not octahedral". J. Am. Chem. Soc. 112 (11): 4547–4549. doi:10.1021/ja00167a065.
Jump up ^ Anslyn, E. V.; Dougherty, D. A. (2006). Modern Physical Organic Chemistry. University Science Books. p. 57. ISBN 978-1891389313.
Further reading[edit]
Lagowski, J. J., ed. (2004). Chemistry: Foundations and Applications. 3. New York: Macmillan. pp. 99–104. ISBN 0-02-865721-7.
External links[edit]
The Wikibook A-level Chemistry/OCR (Salters) has a page on the topic of: Molecular geometry and lone pairs
3D Chem – Chemistry, structures, and 3D Molecules
IUMSC – Indiana University Molecular Structure Center
[hide]
v
t
e
Molecular geometry
Coordination number 2
Linear
Bent
Coordination number 3
Trigonal planar
Trigonal pyramidal
T-shaped
Coordination number 4
Tetrahedral
Square planar
Seesaw
Coordination number 5
Trigonal bipyramidal
Square pyramidal
Pentagonal planar
Coordination number 6
Octahedral
Trigonal prismatic
Pentagonal pyramidal
Distorted octahedral
Coordination number 7
Pentagonal bipyramidal
Coordination number 8
Square antiprismatic
Coordination number 9
Tricapped trigonal prismatic
Capped square antiprismatic

Authority control
GND: 4273775-8
Retrieved from "https://en.wikipedia.org/w/index.php?title=VSEPR_theory&oldid=800749461"
Categories:
Chemistry theories
Molecular geometry
Stereochemistry
Quantum chemistry
Hidden categories:
CS1 uses Japanese-language script (ja)
CS1 Japanese-language sources (ja)
All articles with unsourced statements
Articles with unsourced statements from June 2014
Articles with unsourced statements from February 2017
Articles with unsourced statements from May 2014
Wikipedia articles with GND identifiers
Navigation menu
Personal tools
Not logged in
Talk
Contributions
Create account
Log in
Namespaces
Article
Talk
Variants
Views
Read
Edit
View history
More
Search
Navigation
Main page
Contents
Featured content
Current events
Random article
Donate to Wikipedia
Wikipedia store
Interaction
Help
About Wikipedia
Community portal
Recent changes
Contact page
Tools
What links here
Related changes
Upload file
Special pages
Permanent link
Page information
Wikidata item
Cite this page
Print/export
Create a book
Download as PDF
Printable version
In other projects
Wikimedia Commons
Languages
العربية
Català
Čeština
Deutsch
Español
Esperanto
فارسی
Français
한국어
Bahasa Indonesia
Italiano
עברית
മലയാളം
Nederlands
日本語
Norsk
Polski
Português
Română
Русский
Sicilianu
Suomi
Svenska
தமிழ்
ไทย
Türkçe
Українська
Tiếng Việt
中文
Edit links
This page was last edited on 15 September 2017, at 12:41.
Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
Privacy policy
About Wikipedia
Disclaimers
Contact Wikipedia
Developers
Cookie statement
Mobile view
Enable previews

values: mw-page-base noprint

values: mw-head-base noprint

values: firstHeading firstHeading en

values: siteSub noprint

values: jump-to-nav mw-jump

attrs: href class title

attrs: class style

value: b

value: sup

values:
/wiki/Linear_(chemistry)
mw-redirect
Linear (chemistry)

values:
/wiki/Trigonal_planar
mw-redirect
Trigonal planar

values:
/wiki/Bent_(chemistry)
mw-redirect
Bent (chemistry)

values:
/wiki/Seesaw_(chemistry)
mw-redirect
Seesaw (chemistry)

values:
/wiki/T-shaped_(chemistry)
mw-redirect
T-shaped (chemistry)

values:
/wiki/Square_planar
mw-redirect
Square planar

values: Pentagonal bipyramidal molecular geometry

values: Tricapped trigonal prismatic molecular geometry

values: Capped square antiprismatic molecular geometry

values: This claim needs references to reliable sources. (June 2014)

values:
noprint Inline-Template Template-Fact
white-space:nowrap;

values:
/wiki/Water_(molecule)
mw-redirect
Water (molecule)

values:
/wiki/Trigonal_pyramid_(chemistry)
mw-redirect
Trigonal pyramid (chemistry)

values: This claim needs references to reliable sources. (February 2017)

values: Edit section: Some AX6E1 and AX8E1 molecules

values: Edit section: Transition metal molecules

values:
/wiki/Hybridization_(chemistry)
mw-redirect
Hybridization (chemistry)

values: This claim needs references to reliable sources. (May 2014)

values: List of software for molecular mechanics modeling

values:
nofollow
external text
//doi.org/10.1016%2Fj.ccr.2007.07.007

values:
nofollow
external text
//doi.org/10.1021%2Fed081p298

values:
nofollow
external text
//doi.org/10.1246%2Fnikkashi1921.60.245

values:
nofollow
external text
//doi.org/10.1098%2Frspa.1940.0084

values:
nofollow
external text
//doi.org/10.1039%2FQR9571100339

values:
nofollow
external text
//doi.org/10.1021%2Fed047p18

values:
nofollow
external text
//doi.org/10.1021%2Fed022p145

values:
nofollow
external text
http://maze5.net/?page_id=367

values:
nofollow
external text
//www.worldcat.org/issn/0036-8075

values:
/wiki/PubMed_Identifier
mw-redirect
PubMed Identifier

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/17775218

values:
/wiki/Chem._Soc._Rev.
mw-redirect
Chem. Soc. Rev.

values:
nofollow
external text
//doi.org/10.1039%2Fb405359c

values:
nofollow
external text
//doi.org/10.1021%2Fic00113a023

values:
/wiki/J._Chem._Phys.
mw-redirect
J. Chem. Phys.

values:
nofollow
external text
//doi.org/10.1063%2F1.459748

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/15375262

values:
nofollow
external text
//doi.org/10.1126%2Fscience.1102209

values:
nofollow
external text
//doi.org/10.1063%2F1.1349424

values:
/wiki/J._Am._Chem._Soc.
mw-redirect
J. Am. Chem. Soc.

values:
nofollow
external text
//doi.org/10.1021%2Fja00111a036

values:
nofollow
external text
//doi.org/10.1021%2Fja00167a065

values: -moz-column-width: 30em; -webkit-column-width: 30em; column-width: 30em; list-style-type: decimal;

values: wikibooks:A-level Chemistry/OCR (Salters)/Molecular geometry

values:
nofollow
http://www.3dchem.com/
external text

values:
nofollow
http://www.iumsc.indiana.edu/
external text

values: nowraplinks collapsible autocollapse navbox-inner

values:
nofollow
external text
http://d-nb.info/gnd/4273775-8

values: Category:CS1 uses Japanese-language script (ja)

values: Category:CS1 Japanese-language sources (ja)

values: Category:All articles with unsourced statements

values: Category:Articles with unsourced statements from June 2014

values: Category:Articles with unsourced statements from February 2017

values: Category:Articles with unsourced statements from May 2014

values: Category:Wikipedia articles with GND identifiers

values: Discussion about edits from this IP address [ctrl-alt-n]

values:
/wiki/VSEPR_theory
View the content page [ctrl-alt-c]
c

values: Past revisions of this page [ctrl-alt-h]

values: p-views navigation vectorTabs p-views-label

values:
p-cactions
navigation
vectorMenu emptyPortlet
p-cactions-label

values:
mw-wiki-logo
/wiki/Main_Page
Visit the main page

values:
/wiki/Main_Page
Visit the main page [ctrl-alt-z]
z

values: Featured content – the best of Wikipedia

values: Find background information on current events

values:
/wiki/Special:Random
Load a random article [ctrl-alt-x]
x

values: portal navigation p-navigation p-navigation-label

values: Guidance on how to use and edit Wikipedia

values: About the project, what you can do, where to find things

values: A list of recent changes in the wiki [ctrl-alt-r]

values: portal navigation p-wikibase-otherprojects p-wikibase-otherprojects-label

values:
uls-settings-trigger
Language settings
0
button
true

values: نظرية فيسبر – Arabic

values:
https://es.wikipedia.org/wiki/TREPEV
TREPEV – Spanish
es
es
interlanguage-link-target

values: نظریه دافعه زوج الکترون لایه ظرفیتی – Persian

values: 원자가껍질 전자쌍 반발 이론 – Korean

values: വി.എസ്.ഇ.പി.ആർ സിദ്ധാന്തം – Malayalam

values: 原子価殻電子対反発則 – Japanese

values:
https://pl.wikipedia.org/wiki/VSEPR
VSEPR – Polish
pl
pl
interlanguage-link-target

values: Teoria da repulsão dos pares de elétrons da camada de valência – Portuguese

values: Теория отталкивания электронных пар – Russian

values: வலுவளவு ஓட்டு இலத்திரன் சோடிகளின் தள்ளுகைக் கொள்கை – Tamil

values: ทฤษฎีการผลักกันของคู่อิเล็กตรอนวงเวเลนซ์ – Thai

values: Değerlik kabuğu elektron çifti itmesi – Turkish

values: Теорія відштовхування електронних пар валентних оболонок (ВЕПВО) – Ukrainian

values: 价层电子对互斥理论 – Chinese

values: /static/images/wikimedia-button-1.5x.png 1.5x, /static/images/wikimedia-button-2x.png 2x

values: /static/images/poweredby_mediawiki_132x47.png 1.5x, /static/images/poweredby_mediawiki_176x62.png 2x

values:
suggestions
display: none; font-size: 13px;

values: mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject page-VSEPR_theory rootpage-VSEPR_theory skin-vector action-view


text:
Rotator cuff
From Wikipedia, the free encyclopedia
Jump to: navigation, search
Rotator cuff
Muscles on the dorsum of the scapula, and the triceps brachii.
The scapular and circumflex arteries (posterior view).
Anatomical terminology
[edit on Wikidata]
In anatomy, the rotator cuff (sometimes incorrectly called a "rotator cup", "rotor cuff", or "rotary cup"[1]) is a group of muscles and their tendons that act to stabilize the shoulder. The four muscles of the rotator cuff are over half of the seven scapulohumeral muscles. The four muscles are the supraspinatus muscle, the infraspinatus muscle, teres minor muscle, and the subscapularis muscle.
Contents
[hide]
1 Structure
1.1 Muscles composing rotator cuff
2 Function
3 Clinical significance
3.1 Rotator cuff tear
3.2 Rotator cuff impingement
3.3 Rotator interval inflammation and fibrosis
4 Pain management
4.1 Continuous passive motion
4.2 Capsular release
4.3 Orthotherapy exercises
5 Additional images
6 References
Structure[edit]
Muscles composing rotator cuff[edit]
Muscle Origin on scapula Attachment on humerus Function Innervation
Supraspinatus muscle supraspinous fossa superior[2] facet of the greater tubercle abducts the humerus Suprascapular nerve (C5)
Infraspinatus muscle infraspinous fossa middle facet of the greater tubercle externally rotates the humerus Suprascapular nerve (C5-C6)
Teres minor muscle middle half of lateral border inferior facet of the greater tubercle externally rotates the humerus Axillary nerve (C5)
Subscapularis muscle subscapular fossa lesser tubercle internally rotates the humerus Upper and Lower subscapular nerve (C5-C6)
The supraspinatus muscle spreads out in a horizontal band to insert on the superior and middle facets of the greater tubercle. The greater tubercle projects as the most lateral structure of the humeral head. Medial to this, in turn, is the lesser tuberosity of the humeral head. The subscapularis muscle origin is divided from the remainder of the rotator cuff origins as it is deep to the scapula.
The four tendons of these muscles converge to form the rotator cuff tendon. These tendinous insertions along with the articular capsule, the coracohumeral ligament, and the glenohumeral ligament complex, blend into a confluent sheet before insertion into the humeral tuberosities.[3] The insertion site of the rotator cuff tendon at the greater tuberosity is often referred to as the footprint. The infraspinatus and teres minor fuse near their musculotendinous junctions, while the supraspinatus and subscapularis tendons join as a sheath that surrounds the biceps tendon at the entrance of the bicipital groove.[3] The supraspinatus is most commonly involved in a rotator cuff tear.
Function[edit]
The rotator cuff muscles are important in shoulder movements and in maintaining glenohumeral joint (shoulder joint) stability.[4] These muscles arise from the scapula and connect to the head of the humerus, forming a cuff at the shoulder joint. They hold the head of the humerus in the small and shallow glenoid fossa of the scapula. The glenohumeral joint has been analogously described as a golf ball (head of the humerus) sitting on a golf tee (glenoid fossa).[5]
During abduction of the arm, moving it outward and away from the trunk, the rotator cuff compresses the glenohumeral joint, a term known as concavity compression, in order to allow the large deltoid muscle to further elevate the arm. In other words, without the rotator cuff, the humeral head would ride up partially out of the glenoid fossa, lessening the efficiency of the deltoid muscle. The anterior and posterior directions of the glenoid fossa are more susceptible to shear force perturbations as the glenoid fossa is not as deep relative to the superior and inferior directions. The rotator cuff's contributions to concavity compression and stability vary according to their stiffness and the direction of the force they apply upon the joint.
In addition to stabilizing the glenohumeral joint and controlling humeral head translation, the rotator cuff muscles also perform multiple functions, including abduction, internal rotation, and external rotation of the shoulder. The infraspinatus and subscapularis have significant roles in scapular plane shoulder abduction (scaption), generating forces that are two to three times greater than the force produced by the supraspinatus muscle.[6] However, the supraspinatus is more effective for general shoulder abduction because of its moment arm.[7] The anterior portion of the supraspinatus tendon is submitted to significantly greater load and stress, and performs its mainfunctional role.[8]
Clinical significance[edit]
Rotator cuff tear[edit]
Main article: Rotator cuff tear
The tendons at the ends of the rotator cuff muscles can become torn, leading to pain and restricted movement of the arm. A torn rotator cuff can occur following a trauma to the shoulder or it can occur through the "wear and tear" on tendons, most commonly the supraspinatus tendon found under the acromion.
Rotator cuff injuries are commonly associated with motions that require repeated overhead motions or forceful pulling motions. Such injuries are frequently sustained by athletes whose actions include making repetitive throws, athletes such as baseball pitchers, softball pitchers, American football players (especially quarterbacks), cheerleaders, weightlifters (especially powerlifters due to extreme weights used in the bench press), rugby players, volleyball players (due to their swinging motions),[citation needed] water polo players, rodeo team ropers, shot put throwers (due to using poor technique),[citation needed] swimmers, boxers, kayakers, western martial artists, fast bowlers in cricket, tennis players (due to their service motion)[citation needed] and tenpin bowlers due to the repetitive swinging motion of the arm with the weight of a bowling ball. This type of injury also commonly affects orchestra conductors, choral conductors, and drummers (due, again, to swinging motions).
Treatment for a rotator cuff tear can include rest, ice, physical therapy, and/or surgery[9]. A published review of 14 trials involving 829 patients found that there is insufficient evidence to demonstrate whether surgery is any better than non-surgical options[10]. A review of manual therapy and exercise treatments found inconclusive evidence as to whether these treatments were any better than placebo, however "High quality evidence from one trial suggested that manual therapy and exercise improved function only slightly more than placebo at 22 weeks, was little or no different to placebo in terms of other patient-important outcomes (e.g. overall pain), and was associated with relatively more frequent but mild adverse events."[11]
If a surgical option is selected, the rehabilitation of the rotator cuff is necessary in order to regain maximum strength and range of motion within the shoulder joint.[12] Physical therapy progresses through four stages, increasing movement throughout each phase. The tempo and intensity of the stages are solely reliant on the extent of the injury and the patient’s activity necessities.[13] The first stage requires immobilization of the shoulder joint. The shoulder that is injured is placed in a sling and shoulder flexion or abduction of the arm is avoided for 4 to 6 weeks after surgery (Brewster, 1993). Avoiding movement of the shoulder joint allows the torn tendon to fully heal.[12] Once the tendon is entirely recovered, passive exercises can be implemented. Passive exercises of the shoulder are movements in which a physical therapist maintains the arm in a particular position, manipulating the rotator cuff without any effort by the patient.[14] These exercises are used to increase stability, strength and range of motion of the Subscapularis, Supraspinatus, Infraspinatus, and Teres minor muscles within the rotator cuff.[14] Passive exercises include internal and external rotation of the shoulder joint, as well as flexion and extension of the shoulder.[14]
Physical therapy of shoulder
As progression increases after 4–6 weeks, active exercises are now implemented into the rehabilitation process. Active exercises allow an increase in strength and further range of motion by permitting the movement of the shoulder joint without the support of a physical therapist.[15] Active exercises include the Pendulum exercise (as shown in Image 2), which is used to strengthen the Supraspinatus, Infraspinatus, and Subscapularis.[15] External rotation of the shoulder with the arm at a 90-degree angle is an additional exercise done to increase control and range of motion of the Infraspinatus and Teres minor muscles. Various active exercises are done for an additional 3–6 weeks as progress is based on an individual case by case basis.[15] At 8–12 weeks, strength training intensity will increase as free-weights and resistance bands will be implemented within the exercise prescription.[6]
Rotator cuff impingement[edit]
Main article: Impingement syndrome
A systematic review of relevant research found that the accuracy of the physical examination is low.[16] The Hawkins-Kennedy test[17][18] has a sensitivity of approximately 80% to 90% for detecting impingement. The infraspinatus and supraspinatus[19] tests have a specificity of 80% to 90%.[16]
A common cause of shoulder pain in rotator cuff impingement syndrome is Tendinosis, which is an age related and most often self limited condition.[20]
Rotator interval inflammation and fibrosis[edit]
The rotator interval is a triangular space in the shoulder that is functionally reinforced externally by the coracohumeral ligament and internally by the superior glenohumeral ligament, and traversed by the intra-articular biceps tendon. On imaging, it is defined by the coracoid process at its base, the supraspinatus tendon superiorly and the subscapularis tendon inferiorly. Changes of adhesive capsulitis can be seen at this interval as edema and fibrosis. Pathology at the interval is also associated with glenohumeral and biceps instability.[21]
Pain management[edit]
The rotator cuff includes muscles such as the supraspinatus muscle, the infraspinatus muscle, the teres minor muscle and the subscapularis muscle. The upper arm consists of the deltoids, biceps, as well as the triceps. Steps must be taken and precautions need to be made in order for the rotator cuffs to heal properly following surgery while still maintaining function to prevent any deteriorating effects on the muscles. In the immediate postoperative period (within one week following surgery), pain can be treated with a standard ice wrap. There are also commercial devices available which not only cool the shoulder but also exert pressure on the shoulder ("compressive cryotherapy"). However, one study has shown no significant difference in postoperative pain when comparing these devices to a standard ice wrap.[22]
Continuous passive motion[edit]
Physiotherapy can help manage the pain, but utilizing a program that involves continuous passive motion will reduce the pain even further. Assisted passive motion at a low intensity allows the tissues to be stretched slightly without damaging them[23] Continuous passive motion improves the shoulder range and enables the subject to expand their range of motion without experiencing additional pain. Easing into the motions will allow the person to continue working those muscles to keep them from undergoing atrophy, while also still maintaining that minimum level of function where daily function is allowed. Doing these exercises will also prevent tears in the muscles that will impair daily function further.[23] Since injuries of the rotator cuff often tend to inhibit motion without first experience discomfort and pain, other methods can be done to help accommodate that.
Capsular release[edit]
A surgery procedure exists where the joint of the injured area will be freed in order to achieve a full range of motion without too much pain and discomfort, speeding up recovery time and allowing the person to better perform optimally. A study conducted by Jin-Young Park investigated the benefits of using capsular release to help relieve the stiffness of the shoulders that usually come whenever there is an injury in the rotator cuff. Some of the subjects had diabetes mellitus, which can also cause shoulder stiffness, impeding external rotation of the shoulders. Of the 49 subjects recruited for this trial, 21 went through only manipulation to relieve stiffness, while the other 28 underwent a capsular release surgery along with the manipulation to treat shoulder stiffness. Although, overall, no improvement in outcome was seen with regards to external rotation between the control and treatment group, the subjects that had diabetes mellitus benefited from the treatment that included the capsular release surgery.[24] Their rotator cuff function improved significantly in both forward flexion and external rotation compared to the subjects that were not diagnosed with diabetes mellitus.
Orthotherapy exercises[edit]
Patients that suffer from pain in the rotator cuff may consider utilizing orthotherapy into their daily lives. Orthotherapy is an exercise program that aims to restore the motion and strength of the shoulder muscles.[25] Patients can go through the three phases of orthotherapy to help manage pain and also recover their full range of motion in the rotator cuff. The first phase involves gentle stretches and passive all around movements, and people are advised not to go above 70 degrees of elevation to prevent any kind of further pain.[25] The second phase of this regimen requires patients to implement exercises to strengthen the muscles that are surrounding the rotator cuff muscles, combined with the passive exercises done in the first phase to keep on stretching the tissues without overexerting them. Exercises include pushups and shoulder shrugs, and after a couple of weeks of this, daily activities are gradually added to the patient’s routine. This program does not require any sort of medication or surgery and can serve as a good alternative. The rotator cuff and the upper muscles are responsible for many daily tasks that people do in their lives. A proper recovery needs to be maintained and achieved to prevent limiting movement, and can be done through simple movements.
Additional images[edit]
Diagram of the human shoulder joint
Suprascapular and axillary nerves of right side, seen from behind.
The suprascapular, axillary, and radial nerves.
References[edit]
This article uses anatomical terminology; for an overview, see Anatomical terminology.
Jump up ^ Hartman, B.; Robertson, M. "Push-Ups, Face Pulls, and Shrugs ...for Strong and Healthy Shoulders!". Tnation. The rotator cuff, of course. (Or for those of you from Indiana, that would be your "rotary cup"
Jump up ^ Grays Anatomy 40th
^ Jump up to: a b Matava MJ, Purcell DB, Rudzki JR (2005). "Partial-thickness rotator cuff tears". Am J Sports Med. 33 (9): 1405–17. doi:10.1177/0363546505280213. PMID 16127127.
Jump up ^ Morag Y, Jacobson JA, Miller B, De Maeseneer M, Girish G, Jamadar D (2006). "MR imaging of rotator cuff injury: what the clinician needs to know". Radiographics. 26 (4): 1045–65. doi:10.1148/rg.264055087. PMID 16844931.
Jump up ^ Khazzam M, Kane SM, Smith MJ (2009). "Open shoulder stabilization procedure using bone block technique for treatment of chronic glenohumeral instability associated with bony glenoid deficiency" (PDF). Am J. Orthop. 38 (7): 329–35. PMID 19714273.
^ Jump up to: a b Escamilla RF, Yamashiro K, Paulos L, Andrews JR (2009). "Shoulder muscle activity and function in common shoulder rehabilitation exercises". Sports Med. 39 (8): 663–85. doi:10.2165/00007256-200939080-00004. PMID 19769415.
Jump up ^ Arend, C.F. (2013). "01.1 Rotator Cuff: Anatomy and Function". Ultrasound of the Shoulder. Master Medical Books. ShoulderUS.com]
Jump up ^ Itoi E, Berglund LJ, Grabowski JJ, Schultz FM, Growney ES, Morrey BF, An KN (1995). "Tensile properties of the supraspinatus tendon". J. Orthop. Res. 13 (4): 578–84. doi:10.1002/jor.1100130413. PMID 7674074.
Jump up ^ "Rotator cuff injury - Treatment". Mayo Clinic. Retrieved 2017-09-10.
Jump up ^ Coghlan, Jennifer A; Buchbinder, Rachelle; Green, Sally; Johnston, Renea V; Bell, Simon N (2008-01-23). Cochrane Database of Systematic Reviews. John Wiley & Sons, Ltd. doi:10.1002/14651858.cd005619.pub2/abstract.
Jump up ^ "Manual therapy and exercise for rotator cuff disease | Cochrane". doi:10.1002/14651858.CD012224.
^ Jump up to: a b Brewster C, Schwab DR (1993). "Rehabilitation of the shoulder following rotator cuff injury or surgery". J Orthop Sports Phys Ther. 18 (2): 422–6. doi:10.2519/jospt.1993.18.2.422. PMID 8364597.
Jump up ^ Kuhn JE (2009). "Exercise in the treatment of rotator cuff impingement: a systematic review and a synthesized evidence-based rehabilitation protocol". J Shoulder Elbow Surg. 18 (1): 138–60. doi:10.1016/j.jse.2008.06.004. PMID 18835532.
^ Jump up to: a b c Waltrip RL, Zheng N, Dugas JR, Andrews JR (2003). "Rotator cuff repair. A biomechanical comparison of three techniques". Am J Sports Med. 31 (4): 493–7. PMID 12860534.
^ Jump up to: a b c Jobe FW, Moynes DR (1982). "Delineation of diagnostic criteria and a rehabilitation program for rotator cuff injuries". Am J Sports Med. 10 (6): 336–9. doi:10.1177/036354658201000602. PMID 7180952.
^ Jump up to: a b Hegedus EJ, Goode A, Campbell S, et al. (February 2008). "Physical examination tests of the shoulder: a systematic review with meta-analysis of individual tests". British Journal of Sports Medicine. 42 (2): 80–92. doi:10.1136/bjsm.2007.038406. PMID 17720798.
Jump up ^ ShoulderDoc.co.uk Shoulder & Elbow Surgery. "Hawkins-Kennedy Test". Retrieved 2007-09-12. (video)
Jump up ^ Brukner P, Khan K, Kibler WB. "Chapter 14: Shoulder Pain". Retrieved 2007-08-30.
Jump up ^ ShoulderDoc.co.uk Shoulder & Elbow Surgery. "Empty Can/Full Can Test". Retrieved 2007-09-12. (video)
Jump up ^ Mohamadi, Amin; Chan, Jimmy J.; Claessen, Femke M. A. P.; Ring, David; Chen, Neal C. (January 2017). "Corticosteroid Injections Give Small and Transient Pain Relief in Rotator Cuff Tendinosis: A Meta-analysis". Clinical Orthopaedics and Related Research. 475 (1): 232–243. doi:10.1007/s11999-016-5002-1. ISSN 1528-1132. PMC 5174041  . PMID 27469590.
Jump up ^ Petchprapa, CN; Beltran, LS; Jazrawi, LM; Kwon, YW; Babb, JS; Recht, MP (September 2010). "The rotator interval: a review of anatomy, function, and normal and abnormal MRI appearance". AJR. American journal of roentgenology. 195 (3): 567–76. doi:10.2214/ajr.10.4406. PMID 20729432.
Jump up ^ Kraeutler, MJ; Reynolds, KA; Long, C; McCarty, EC (Jun 2015). "Compressive cryotherapy versus ice-a prospective, randomized study on postoperative pain in patients undergoing arthroscopic rotator cuff repair or subacromial decompression". Journal of Shoulder & Elbow Surgery. 24 (6): 854–859. doi:10.1016/j.jse.2015.02.004. PMID 25825138.
^ Jump up to: a b Plessis, M. Du, E. Eksteen, A. Jenneker, E. Kriel, C. Mentoor, T. Stucky, D. Van Staden, and L. Morris. "The Effectiveness of Continuous Passive Motion on Range of Motion, Pain and Muscle Strength following Rotator Cuff Repair: A Systematic Review." Clinical Rehabilitation (2011): 291-302
Jump up ^ Park, J.-Y., S. W. Chung, Z. Hassan, J.-Y. Bang, and K.-S. Oh. "Effect of Capsular Release in the Treatment of Shoulder Stiffness Concomitant With Rotator Cuff Repair: Diabetes as a Predisposing Factor Associated With Treatment Outcome." The American Journal of Sports Medicine (2014): 840-50. SagePub
^ Jump up to: a b Wirth, Michael A., Carl Basamania, and Charles A. Rockwood. "Nonoperative Management Of Full-Thickness Tears Of The Rotator Cuff." Orthopedic Clinics of North America (1997): 59-67
[hide]
v
t
e
Muscles of the arm
Shoulder
deltoid
rotator cuff
supraspinatus
infraspinatus
teres minor
subscapularis
teres major
fascia:
deltoid fascia
supraspinous fascia
infraspinous fascia
Arm
(compartments)
anterior
coracobrachialis
biceps
brachialis
posterior
triceps brachii
anconeus
articularis cubiti
fascia
axillary sheath
axillary fascia
brachial fascia
intermuscular septa
lateral
medial
other
spaces
quadrangular space
triangular space
triangular interval
Forearm
anterior
superficial:
pronator teres
palmaris longus
flexor carpi radialis
flexor carpi ulnaris
flexor digitorum superficialis
deep:
pronator quadratus
flexor digitorum profundus
flexor pollicis longus
posterior
superficial:
mobile wad
brachioradialis
extensor carpi radialis longus and brevis
extensor digitorum
extensor digiti minimi
extensor carpi ulnaris
deep:
supinator
anatomical snuff box
abductor pollicis longus
extensor pollicis brevis
extensor pollicis longus
extensor indicis
fascia
bicipital aponeurosis
common tendons
extensor
flexor
antebrachial fascia
other
cubital tunnel
Hand
lateral volar
thenar
opponens pollicis
flexor pollicis brevis
abductor pollicis brevis
adductor pollicis
medial volar
hypothenar
opponens digiti minimi
flexor digiti minimi brevis
abductor digiti minimi
palmaris brevis
intermediate
lumbrical
interossei
dorsal
palmar
fascia
posterior:
extensor retinaculum
extensor expansion
anterior:
flexor retinaculum
palmar aponeurosis
Retrieved from "https://en.wikipedia.org/w/index.php?title=Rotator_cuff&oldid=807754210"
Categories:
Rotator cuff
Shoulder
Upper limb anatomy
Hidden categories:
Articles which use infobox templates with no data rows
Medicine infobox template using GraySubject or GrayPage
All articles with unsourced statements
Articles with unsourced statements from June 2012
Articles with unsourced statements from July 2011
Use dmy dates from July 2011
Navigation menu
Personal tools
Not logged in
Talk
Contributions
Create account
Log in
Namespaces
Article
Talk
Variants
Views
Read
Edit
View history
More
Search
Navigation
Main page
Contents
Featured content
Current events
Random article
Donate to Wikipedia
Wikipedia store
Interaction
Help
About Wikipedia
Community portal
Recent changes
Contact page
Tools
What links here
Related changes
Upload file
Special pages
Permanent link
Page information
Wikidata item
Cite this page
Print/export
Create a book
Download as PDF
Printable version
Languages
العربية
Català
Dansk
Deutsch
Español
فارسی
Français
Galego
Bahasa Indonesia
Italiano
עברית
Nederlands
日本語
Norsk
Norsk nynorsk
Polski
Português
Română
Русский
Suomi
Svenska
Edit links
This page was last edited on 29 October 2017, at 23:20.
Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
Privacy policy
About Wikipedia
Disclaimers
Contact Wikipedia
Developers
Cookie statement
Mobile view
Enable previews

key: html

type: local

value: div

attrs: id class

values: mw-page-base noprint

values: mw-head-base noprint

value: a

attrs: id class lang

values: firstHeading firstHeading en

values: siteSub noprint

values: jump-to-nav mw-jump

value: i

value: th

attrs: colspan style

value: tr

value: img

attrs: alt src width height srcset data-file-width data-file-height

attrs: href class

value: td

attrs: href title

values:
/wiki/Human_anatomy
mw-redirect
Human anatomy

values: Edit section: Muscles composing rotator cuff

values:
/wiki/Supraspinous_fossa
mw-redirect
Supraspinous fossa

values:
/wiki/Abduction_(kinesiology)
mw-redirect
Abduction (kinesiology)

values:
/wiki/Infraspinous_fossa
mw-redirect
Infraspinous fossa

values:
/wiki/External_rotation
mw-redirect
External rotation

values:
/wiki/Lateral_border
mw-redirect
Lateral border

values:
/wiki/Subscapular_fossa
mw-redirect
Subscapular fossa

values:
/wiki/Internal_rotation
mw-redirect
Internal rotation

values:
/wiki/Lower_subscapular_nerves
mw-redirect
Lower subscapular nerves

values:
/wiki/Lateral_(anatomy)
mw-redirect
Lateral (anatomy)

values:
/wiki/Glenohumeral_ligament
mw-redirect
Glenohumeral ligament

values:
/wiki/Greater_tuberosity
mw-redirect
Greater tuberosity

values:
/wiki/Teres_minor
mw-redirect
Teres minor

values:
/wiki/Glenohumeral_joint
mw-redirect
Glenohumeral joint

values: This claim needs references to reliable sources. (June 2012)

values:
noprint Inline-Template Template-Fact
white-space:nowrap;

values: This claim needs references to reliable sources. (July 2011)

values:
/wiki/Tenpin_Bowling
mw-redirect
Tenpin Bowling

values:
/wiki/Orchestra_conductor
mw-redirect
Orchestra conductor

values:
/wiki/Choral_conductor
mw-redirect
Choral conductor

values:
/wiki/Immobilization_(pathology)
mw-redirect
Immobilization (pathology)

attrs: alt src width height class srcset data-file-width data-file-height

values:
/wiki/Hawkins-Kennedy_test
mw-redirect
Hawkins-Kennedy test

values:
/wiki/Sensitivity_(tests)
mw-redirect
Sensitivity (tests)

values:
/wiki/Specificity_(tests)
mw-redirect
Specificity (tests)

values: Edit section: Rotator interval inflammation and fibrosis

values:
/wiki/Biceps_tendon
mw-redirect
Biceps tendon

values:
/wiki/Adhesive_capsulitis
mw-redirect
Adhesive capsulitis

values: Mike Robertson (author) (page does not exist)

values:
/wiki/PubMed_Identifier
mw-redirect
PubMed Identifier

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/16127127

values:
nofollow
external text
//doi.org/10.1148%2Frg.264055087

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/16844931

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/19714273

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/19769415

values:
nofollow
http://www.shoulderus.com/
external text

values:
nofollow
external text
//doi.org/10.1002%2Fjor.1100130413

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/7674074

values:
nofollow
external text
//doi.org/10.1002%2F14651858.CD012224

values:
nofollow
external text
//doi.org/10.2519%2Fjospt.1993.18.2.422

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/8364597

values:
nofollow
external text
//doi.org/10.1016%2Fj.jse.2008.06.004

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/18835532

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/12860534

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/7180952

values:
nofollow
external text
//doi.org/10.1136%2Fbjsm.2007.038406

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/17720798

values:
nofollow
external text
//www.worldcat.org/issn/1528-1132

attrs: alt src title width height srcset data-file-width data-file-height

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/27469590

values:
nofollow
external text
//doi.org/10.2214%2Fajr.10.4406

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/20729432

values:
nofollow
external text
//doi.org/10.1016%2Fj.jse.2015.02.004

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/25825138

values: -moz-column-width: 30em; -webkit-column-width: 30em; column-width: 30em; list-style-type: decimal;

values:
/wiki/Anterior_compartment_of_the_arm
mw-redirect
Anterior compartment of the arm

values:
/wiki/Posterior_compartment_of_the_arm
mw-redirect
Posterior compartment of the arm

values:
/wiki/Anatomical_snuff_box
mw-redirect
Anatomical snuff box

values:
/wiki/Opponens_digiti_minimi_muscle
mw-redirect
Opponens digiti minimi muscle

values: Flexor digiti minimi brevis muscle (hand)

values: nowraplinks collapsible autocollapse navbox-inner

values: Category:Articles which use infobox templates with no data rows

values: Category:Medicine infobox template using GraySubject or GrayPage

values: Category:All articles with unsourced statements

values: Category:Articles with unsourced statements from June 2012

values: Category:Articles with unsourced statements from July 2011

values: Discussion about edits from this IP address [ctrl-alt-n]

values: A list of edits made from this IP address [ctrl-alt-y]

values: You are encouraged to create an account and log in; however, it is not mandatory

values: You're encouraged to log in; however, it's not mandatory. [ctrl-alt-o]

values:
/wiki/Rotator_cuff
View the content page [ctrl-alt-c]
c

values: Discussion about the content page [ctrl-alt-t]

values: p-namespaces navigation vectorTabs p-namespaces-label

values:
p-variants
navigation
vectorMenu emptyPortlet
p-variants-label

values: Past revisions of this page [ctrl-alt-h]

values: p-views navigation vectorTabs p-views-label

values:
p-cactions
navigation
vectorMenu emptyPortlet
p-cactions-label

values:
mw-wiki-logo
/wiki/Main_Page
Visit the main page

values:
/wiki/Main_Page
Visit the main page [ctrl-alt-z]
z

values: Featured content – the best of Wikipedia

values: Find background information on current events

values:
/wiki/Special:Random
Load a random article [ctrl-alt-x]
x

values: portal navigation p-navigation p-navigation-label

values: Guidance on how to use and edit Wikipedia

values: About the project, what you can do, where to find things

values: portal navigation p-interaction p-interaction-label

values: List of all English Wikipedia pages containing links to this page [ctrl-alt-j]

values: Recent changes in pages linked from this page [ctrl-alt-k]

values:
/wiki/Wikipedia:File_Upload_Wizard
Upload files [ctrl-alt-u]
u

values: A list of all special pages [ctrl-alt-q]

values: Permanent link to this revision of the page

values: Link to connected data repository item [ctrl-alt-g]

values: Printable version of this page [ctrl-alt-p]

values: كفة مدورة – Arabic

values: ماهیچه‌های گرداننده شانه – Persian

values: מסובבי הכתף – Hebrew

values: Вращательная манжета плеча – Russian

values: mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject page-Rotator_cuff rootpage-Rotator_cuff skin-vector action-view


text:
Kiln
From Wikipedia, the free encyclopedia
Jump to: navigation, search
For other uses, see Kiln (disambiguation).
Charcoal kilns, California
Indian brick kiln
Hops kiln
Farnham Pottery, Wrecclesham, Surrey with the preserved bottle kiln on the right of photo
Catenary arch kiln under construction
An empty, intermittent kiln. This specific example is a "car kiln"; the base is on wheels and has been rolled out of the kiln - this facilitates loading and unloading the kiln
A kiln (/kɪln/ or /kɪl/,[1] originally pronounced "kill", with the "n" silent) is a thermally insulated chamber, a type of oven, that produces temperatures sufficient to complete some process, such as hardening, drying, or chemical changes. Kilns have been used for millennia to turn objects made from clay into pottery, tiles and bricks. Various industries use rotary kilns for pyroprocessing—to calcinate ores, to calcinate limestone to lime for cement, and to transform many other materials.
Contents
[hide]
1 Etymology and pronunciation
2 Uses of kilns
3 Ceramic kilns
3.1 Modern kilns
4 Wood-drying kiln
5 Gallery
6 See also
7 Notes
8 References
9 External links
Etymology and pronunciation[edit]
The word kiln descends from the Old English cylene (/ˈkylene/, which was adapted from the Latin culīna 'kitchen, cooking-stove, burning-place. During the Middle English Period, the "n" was not pronounced, as evidenced by kiln having frequently been spelled without the "n",[2] Another word, "miln", a place where wheat is ground, also had a silent "n". Whereas the spelling of "miln" was changed to "mill" to match its pronunciation, "kiln" maintained its spelling, which most likely led to a common mispronunciation, which has now become commonly used. However, there are small bastions where the original pronunciation has endured. Kiln, Mississippi, a small town known for its wood drying kilns that once served the timber industry, is still referred to as "the Kill" by locals.[3]
Unwittingly adding the "n" sound at the end of "kiln" is due to people being introduced to the word through the written language before ever hearing the actual pronunciation. Linguists call this phenomenon "reading pronunciation" where an incorrect pronunciation is read aloud, becomes widespread, eventually reported by dictionaries, and the "original pronunciation, passed from parent to child, mouth to ear, for many generations is lost."[4]
Phonetically, the "ln" in "kiln" is categorized as a digraph: a combination of two letters that make only one sound, such as the "mn" in "hymn". From English Words as Spoken and Written for Upper Grades by James A. Bowen 1900: "The digraph ln, n silent, occurs in kiln. A fall down the kiln can kill you."[5] Bowen was pointing out the humorous fact that "kill" and "kiln" are homophones.[6] A homophone is a word that is pronounced the same as another word but differs in meaning, and may differ in spelling.[7]

Uses of kilns[edit]
The earliest known kiln dates to around 6000 BC, and was found at the Yarim Tepe site in modern Iraq.[8] Neolithic kilns were able to produce temperatures greater than 900 °C (1652 °F).[9] Uses include:
Annealing, fusing and deforming glass, or fusing metallic oxide paints to the surface of glass
Heat treatment for metallic workpieces
Ceramics
Brickworks
Melting metal for casting
Smelting ore to extract metal
Pylorysis of chemical materials
Heating limestone with clay in the manufacture of Portland cement, the Cement kiln
Heating limestone to make quicklime or calcium oxide, the Lime kiln
Heating gypsum to make plaster of Paris
For cremation (at high temperature)
Drying of tobacco leaves
Drying malted barley for brewing and other fermentations
Drying hops for brewing (known as a hop kiln or oast house)
Drying corn (grain) before grinding or storage, sometimes called a corn kiln, corn drying kiln.[10]
Drying green lumber so it can be used immediately
Drying wood for use as firewood
Heating wood to the point of pyrolysis to produce charcoal
Ceramic kilns[edit]
Kilns are an essential part of the manufacture of all ceramics. Ceramics require heat at high temperatures so chemical and physical reactions will occur to permanently alter the unfired body. In the case of pottery, clay materials are shaped, dried and then fired in a kiln. The final characteristics are determined by the composition and preparation of the clay body, by the temperature at which it is fired. After a first firing glazes may be used and the ware is fired a second time to fuse the glaze into the body. A third firing at a lower temperature may be required to fix overglaze decoration. Modern kilns often have sophisticated electrical control systems to firing regime, although pyrometric devices are often also used.
Clay consists of fine-grained particles, that are relatively weak and porous. Clay is combined with other minerals to create a workable clay body. Part of the firing process includes sintering. This heats the clay until the particles partially melt and flow together, creating a strong, single mass, composed of a glassy phase interspersed with pores and crystalline material. Through firing, the pores are reduced in size, causing the material to shrink slightly. This crystalline material predominantly consists of silicon and aluminium oxides.
In the broadest terms, there are two types of kiln: intermittent and continuous, both sharing the same basic characteristics of being an insulated box with a controlled inner temperature and atmosphere.
A continuous kiln, sometimes called a tunnel kiln, is a long structure in which only the central portion is directly heated. From the cool entrance, ware is slowly transported through the kiln, and its temperature is increased steadily as it approaches the central, hottest part of the kiln. From there, it continues through the kiln, and the surrounding temperature is reduced until it exits the kiln nearly at room temperature. A continuous kiln is energy-efficient, because heat given off during cooling is recycled to pre-heat the incoming ware. In some designs, the ware is left in one place, while the heating zone moves across it. Kilns in this type include:
Hoffmann kiln
Bull’s Trench kiln
Habla (Zig-Zag) kiln
Roller kiln:A special type of kiln, common in tableware and tile manufacture, is the roller-hearth kiln, in which wares placed on bats are carried through the kiln on rollers.
In the intermittent kiln. the ware to be fired is placed into the kiln. The kiln is closed, and the internal temperature increased according to a schedule. After the firing is completed, both the kiln and the ware are cooled. The ware is removed, the kiln is cleaned and the next cycle begins. Kilns in this type include:[11]
Clamp kiln
Skove kiln
Scotch kiln
Down-Draft kiln
Shuttle Kilns: this is a car-bottom kiln with a door on one or both ends. Burners are positioned top and bottom on each side, creating a turbulent circular air flow. This type of kiln is generally a multi-car design and is used for processing whitewares, technical ceramics and refractories in batches. Depending upon size and mass of ware, shuttle kilns may be equipped with car moving devices to transfer fired and unfired ware in and out of the kiln. Shuttle kilns can be either updraft or downdraft in design. A Shuttle Kiln derives its name from the fact that kiln cars can enter a shuttle kiln from either end of the kiln for processing, whereas a tunnel kiln has flow in only one direction.
Kiln technology is very old. The development of the kiln from a simple earthen trench filled with pots and fuel, pit firing, to modern methods happened in stages. One improvement was to build a firing chamber around pots with baffles and a stoking hole. This conserved heat. A chimney stack improves the air flow or draw of the kiln, thus burning the fuel more completely.
Chinese kiln technology has always been a key factor in the development of Chinese pottery, and until recent centuries was far ahead of other parts of the world. The Chinese developed effective kilns capable of firing at around 1,000°C before 2000 BC. These were updraft kilns, often built below ground. Two main types of kiln were developed by about 200 AD and remained in use until modern times. These are the dragon kiln of hilly southern China, usually fuelled by wood, long and thin and running up a slope, and the horseshoe-shaped mantou kiln of the north Chinese plains, smaller and more compact. Both could reliably produce the temperatures of up to 1300°C or more needed for porcelain. In the late Ming, the egg-shaped kiln or zhenyao was developed at Jingdezhen, but mainly used there. This was something of a compromise between the other types, and offered locations in the firing chamber with a range of firing conditions.[12]
Both Ancient Roman pottery and medieval Chinese pottery could be fired in industrial quantities, with tens of thousands of pieces in a single firing.[13] Early examples of simpler kilns found in Britain include those that made roof-tiles during the Roman occupation. These kilns were built up the side of a slope, such that a fire could be lit at the bottom and the heat would rise up into the kiln.
Traditional kilns include:
Dragon kiln of south China: thin and long, climbing up a hillside. This type spread to the rest of East Asia giving the Japanese Anagama kiln, arriving via Korea in the 5th century. This kiln usually consists of one long firing chamber, pierced with smaller ware stacking ports on one side, with a firebox at one end and a flue at the other. Firing time can vary from one day to several weeks. Traditional anagama kilns are also built on a slope to allow for a better draft. The Japanese Noborigama kiln is an evolution from Anagama design as a multi-chamber kiln where wood is stacked from the front firebox at first, then only through the side-stoking holes with the benefit of having air heated up to 600 °C (1,112 °F) from the front firebox, enabling more efficient firings.
During the reconstitution of a traditional Cambodian kiln at Khmer Ceramics & fine arts centre in Siem Reap Cambodia
Khmer Kiln: quite similar to the Anagama kiln; however, traditional Khmer Kilns had a flat roof. Chinese, Korean or Japanese kilns have an arch roof. These types of kiln vary in size and can measure in the tens of meters. The firing time also varies and can last several days.
Bottle kiln: a type of intermittent kiln, usually coal-fired, formerly used in the firing of pottery; such a kiln was surrounded by a tall brick hovel or cone, of typical bottle shape. The tableware was enclosed in sealed fireclay saggars, as the heat and smoke from the fires passed through the oven it would be fired at temperatures up to 1,400 °C (2,552 °F).
Biscuit kiln: The first firing would take place in the biscuit kiln
Glost kiln: The biscuit-ware was glazed and given a second glost firing in the larger glost kilns
Mantou kiln of north China, smaller and more compact than the dragon kiln.
Muffle Kiln: This was used to fire over-glaze decoration, at a temperature under 800 °C (1,472 °F). in these cool kilns the smoke from the fires passed through flues outside the oven.
Catenary arch kiln: Typically used for the firing of pottery using salt, these by their form (a catenary arch) tend to retain their shape over repeated heating and cooling cycles, whereas other types require extensive metalwork supports.
Sèvres kiln: invented in Sèvres, France, it efficiently generated high-temperatures 1,240 °C (2,264 °F) to produce waterproof ceramic bodies and easy-to-obtain glazes. It features a down-draft design that produces high temperature in shorter time, even with wood-firing.
Bourry box kiln, similar to previous one.
Modern kilns[edit]
With the industrial age, kilns were designed to use electricity and more refined fuels, including natural gas and propane. Many large industrial pottery kilns use natural gas, as it is generally clean, efficient and easy to control. Modern kilns can be fitted with computerized controls allowing for fine adjustments during the firing. A user may choose to control the rate of temperature climb or ramp, hold or soak the temperature at any given point, or control the rate of cooling. Both electric and gas kilns are common for smaller scale production in industry and craft, handmade and sculptural work.
Modern kilns include:
Retort kiln: a type of kiln which can reach temperatures around 1,500 °C (2,732 °F) for extended periods of time. Typically, these kilns are used in industrial purposes, and feature movable charging cars which make up the bottom and door of the kiln.
Electric kilns: kilns operated by electricity were developed in the 20th century, primarily for smaller scale use such as in schools, universities, and hobby centers. The atmosphere in most designs of electric kiln is rich in oxygen, as there is no open flame to consume oxygen molecules. However, reducing conditions can be created with appropriate gas input, or by using saggars in a particular way.
Feller kiln: brought contemporary design to wood firing by re-using unburnt gas from the chimney to heat intake air before it enters the firebox. This leads to an even shorter firing cycle and less wood consumption. This design requires external ventilation to prevent the in-chimney radiator from melting, being typically in metal. The result is a very efficient wood kiln firing one cubic metre of ceramics with one cubic meter of wood.[citation needed]
Microwave assisted firing: this technique combine microwave energy with more conventional energy sources, such as radiant gas or electric heating, to process ceramic materials to the required high temperatures. Microwave-assisted firing offers significant economic benefits.
Top-hat kiln: an intermittent kiln of a type sometimes used to fire pottery. The ware is set on a refractory hearth, or plinth, over which a box-shaped cover is lowered.
Wood-drying kiln[edit]
Main article: Wood drying § Kiln drying
Green wood coming straight from the felled tree has far too high a moisture content to be commercially useful and will rot, warp and split. Both hardwoods and softwood must be left to dry out until the moisture content is between 18% and 8%. This can be a long process, or it is speeded up by use of a kiln. A variety of kiln technologies exist today: conventional, dehumidification, solar, vacuum and radio frequency.
Conventional wood dry
[14] are either package-type (side-loader) or track-type (tram) construction. Most hardwood lumber kilns are side-loader kilns in which fork trucks are used to load lumber packages into the kiln. Most softwood kilns are track types in which the timber (US. lumber) is loaded on kiln/track cars for loading the kiln. Modern high-temperature, high-air-velocity conventional kilns can typically dry 1-inch-thick (25 mm) green wood in 10 hours down to a moisture content of 18%. However, 1-inch-thick green Red Oak requires about 28 days to dry down to a moisture content of 8%.
Heat is typically introduced via steam running through fin/tube heat exchangers controlled by on/off pneumatic valves. Humidity is removed by a system of vents, the specific layout of which are usually particular to a given manufacturer. In general, cool dry air is introduced at one end of the kiln while warm moist air is expelled at the other. Hardwood conventional kilns also require the introduction of humidity via either steam spray or cold water misting systems to keep the relative humidity inside the kiln from dropping too low during the drying cycle. Fan directions are typically reversed periodically to ensure even drying of larger kiln charges.
Most softwood kilns operate below 115 °C (239 °F) temperature. Hardwood kiln drying schedules typically keep the dry bulb temperature below 80 °C (176 °F). Difficult-to-dry species might not exceed. 60 °C (140 °F)
Dehumidification kilns
are similar to other kilns in basic construction and drying times are usually comparable. Heat comes primarily from an integral dehumidification unit that also removes humidity. Auxiliary heat is often provided early in the schedule to supplement the dehumidifier.
Solar kilns
are conventional kilns, typically built by hobbyists to keep initial investment costs low. Heat is provided via solar radiation, while internal air circulation is typically passive.
Vacuum and radio frequency kilns
reducing the air pressure to attempt to speed up the drying process. A variety of these vacuum technologies exist, varying primarily in the method heat is introduced into the wood charge. Hot water platten vacuum kilns use aluminum heating plates with the water circulating within as the heat source, and typically operate at significantly reduced absolute pressure. Discontinuous and SSV (super-heated steam) use atmosphere pressure to introduce heat into the kiln charge. The entire kiln charge comes up to full atmospheric pressure, the air in the chamber is then heated and finally a vacuum is pulled as the charge cools. SSV run at partial-atmospheres, typically around 1/3 of full atmospheric pressure, in a hybrid of vacuum and conventional kiln technology (SSV kilns are significantly more popular in Europe where the locally harvested wood is easier to dry than the North American woods. RF/V (radio frequency + vacuum) kilns use microwave radiation to heat the kiln charge, and typically have the highest operating cost due to the heat of vaporization being provided by electricity rather than local fossil fuel or waste wood sources.
The economics of different wood drying technologies are based on the total energy, capital, insurance/risk, environmental impacts, labor, maintenance, and product degradation costs. These costs which can be a significant part of plant costs, involve the differential impact of the presence of drying equipment in a specific plant. Every piece of equipment from the green trimmer to the infeed system at the planer mill is part the "drying system". The true costs of the drying system can only be determined when comparing the total plant costs and risks with and without drying.
Kiln dried firewood was pioneered during the 1980s, this was later adopted extensively in Europe due to the economic and practical benefits of selling wood with a lower moisture content.[15] [16][17]
The total (harmful) air emissions produced by wood kilns, including their heat source, can be significant. Typically, the higher the temperature the kiln operates at, the larger amount of emissions are produced (per pound of water removed). This is especially true in the drying of thin veneers and high-temperature drying of softwoods.
Gallery[edit]
Brickmaking kilns, Mekong delta. The cargo boat in the foreground is carrying the rice chaff used as fuel for the firing.
A wood fired pottery kiln in Hoi An Vietnam.
A Catenary Arch kiln used for firing high temperature electron tube grade aluminium oxide ceramics
A two-story porcelain kiln with furnaces á alandier in Sèvres, France circa 1880
CAD representation of a Beehive Kiln
CAD representation of a Tunnel kiln
See also[edit]
Forge
Furnace
List of ovens
Top-lit updraft gasifier
Notes[edit]
Jump up ^ "kiln". Merriam-Webster Dictionary. Retrieved 2016-08-29.
Jump up ^ "kiln". Oxford English Dictionary (3rd ed.). Oxford University Press. September 2005. (Subscription or UK public library membership required.)
Jump up ^ https://books.google.com/books?id=eJOsaFMnOyIC&pg=PA12&lpg=PA12&dq=%22The+Kill%22+mississippi+kiln&source=bl&ots=WPex6XiAy5&sig=BzmCZJLDbXrIlVElp4ecPSJMI7A&hl=en&sa=X&ved=0ahUKEwjFzPSzlK7PAhUC0GMKHZnIAK4Q6AEINzAF#v=onepage&q=%22The%20Kill%22%20mississippi%20kiln&f=false
Jump up ^ http://www.ampersandvirgule.com/2007/04/jumpin-up-and-down-yelling-kiln-kiln.html
Jump up ^ https://books.google.com/books?id=Y7xHAQAAMAAJ
Jump up ^ http://www.homophone.com/h/kill-kiln
Jump up ^ http://www.dictionary.com/browse/homophone
Jump up ^ Piotr Bienkowski; Alan Millard (15 April 2010). Dictionary of the Ancient Near East. University of Pennsylvania Press. p. 233. ISBN 978-0-8122-2115-2.
Jump up ^ James E. McClellan III; Harold Dorn. Science and Technology in World History: An Introduction. JHU Press; 14 April 2006. ISBN 978-0-8018-8360-6. p. 21.
Jump up ^ Conran, Sheelagh; et al. (2011). Past Times, Changing Fortunes. Proceedings of a public seminar on archaeological discoveries on national road schemes. ARCHAEOLOGY AND THE NATIONAL ROADS AUTHORITY, Monograph Series No.8. Dublin: Transport Infrastructure Ireland. pp. 73–84. ISBN 9780956418050. CS1 maint: Explicit use of et al. (link)
Jump up ^ "Small Scale Brickmaking".
Jump up ^ Rawson, 364, 369-370; Vainker, 222-223; JP Hayes article from the Grove Dictionary of Art
Jump up ^ Vainker, 222-223; JP Hayes article from the Grove Dictionary of Art
Jump up ^ Rasmussen 1988.
Jump up ^ Maviglio, S. 1986. From stump to stove in three days. Yankee. 50(12): 95-96(December).
Jump up ^ http://www.fpl.fs.fed.us/documnts/fplrn/fplrn254.pdf
Jump up ^ "Important information and facts about our firewood". www.certainlywood.co.uk. Retrieved 2016-10-27.
References[edit]
Hamer, Frank and Janet. The Potter's Dictionary of Materials and Techniques. A & C Black Publishers, Limited, London, England, Third Edition 1991. ISBN 0-8122-3112-0.
Smith, Ed. Dry Kiln Design Manual. J.E. Smith Engineering and Consulting, Blooming Grove, Texas. Available for purchase from author J.E. Smith
M. Kornmann and CTTB, "Clay bricks and roof tiles, manufacturing and properties", Soc. industrie minérale, Paris,(2007) ISBN 2-9517765-6-X
Rasmussen, E.F. (1988). Forest Products Laboratory, U.S. Department of Agriculture., ed. Dry Kiln Operators Manual. Hardwood Research Council.
External links[edit]
Wikimedia Commons has media related to Kilns.
Look up kiln in Wiktionary, the free dictionary.
Kilns and Firing Structures entry in the UCLA Encyclopedia of Egyptology
Information about the history of bottle ovens (kilns) from Gladstone Pottery Museum in Stoke-on-Trent, UK.
How the Bottle Kiln Works (from thepotteries.org)
Retrieved from "https://en.wikipedia.org/w/index.php?title=Kiln&oldid=821547816"
Categories:
Industrial furnaces
Pottery
Kilns
Hidden categories:
CS1 maint: Explicit use of et al.
All articles with unsourced statements
Articles with unsourced statements from February 2015
Navigation menu
Personal tools
Not logged in
Talk
Contributions
Create account
Log in
Namespaces
Article
Talk
Variants
Views
Read
Edit
View history
More
Search
Navigation
Main page
Contents
Featured content
Current events
Random article
Donate to Wikipedia
Wikipedia store
Interaction
Help
About Wikipedia
Community portal
Recent changes
Contact page
Tools
What links here
Related changes
Upload file
Special pages
Permanent link
Page information
Wikidata item
Cite this page
Print/export
Create a book
Download as PDF
Printable version
In other projects
Wikimedia Commons
Languages
Català
Cymraeg
Deutsch
Español
Euskara
Français
Gaeilge
Gàidhlig
한국어
हिन्दी
Bahasa Indonesia
日本語
Oʻzbekcha/ўзбекча
Polski
Scots
Simple English
Українська
中文
Edit links
This page was last edited on 21 January 2018, at 04:34.
Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
Privacy policy
About Wikipedia
Disclaimers
Contact Wikipedia
Developers
Cookie statement
Mobile view
Enable previews

values: mw-page-base noprint

values: mw-head-base noprint

values: firstHeading firstHeading en

values: siteSub noprint

values: jump-to-nav mw-jump

values:
/wiki/Kiln_(disambiguation)
mw-disambig
Kiln (disambiguation)

attrs: role class

values:
note
hatnote navigation-not-searchable

values: Edit section: Etymology and pronunciation

values: Representation in the International Phonetic Alphabet (IPA)

values:
/wiki/Plaster_of_Paris
mw-redirect
Plaster of Paris

values:
/wiki/Chinese_pottery
mw-redirect
Chinese pottery

values:
/wiki/Egg-shaped_kiln
mw-redirect
Egg-shaped kiln

values:
/wiki/Glost_firing
mw-redirect
Glost firing

values:
/wiki/Industrial_age
mw-redirect
Industrial age

values: This claim needs references to reliable sources. (February 2015)

values:
noprint Inline-Template Template-Fact
white-space:nowrap;

values:
/wiki/Mekong_delta
mw-redirect
Mekong delta

values: font-size:0.95em; font-size: 90%; color: #555

values:
nofollow
external free
http://www.homophone.com/h/kill-kiln

values: Category:CS1 maint: Explicit use of et al.

values:
nofollow
external text
http://www.jesmitheng.com/books.html

values:
nofollow
external text
http://escholarship.org/uc/nelc_uee

values: Category:All articles with unsourced statements

values: Category:Articles with unsourced statements from February 2015

values: Discussion about edits from this IP address [ctrl-alt-n]

values: A list of edits made from this IP address [ctrl-alt-y]

values: You are encouraged to create an account and log in; however, it is not mandatory

values: You're encouraged to log in; however, it's not mandatory. [ctrl-alt-o]

values:
/wiki/Kiln
View the content page [ctrl-alt-c]
c

values: Discussion about the content page [ctrl-alt-t]

values: p-namespaces navigation vectorTabs p-namespaces-label

values:
p-variants
navigation
vectorMenu emptyPortlet
p-variants-label

values:
/w/index.php?title=Kiln&action=edit
Edit this page [ctrl-alt-e]
e

values: Past revisions of this page [ctrl-alt-h]

values: p-views navigation vectorTabs p-views-label

values:
p-cactions
navigation
vectorMenu emptyPortlet
p-cactions-label

values:
mw-wiki-logo
/wiki/Main_Page
Visit the main page

values: A list of recent changes in the wiki [ctrl-alt-r]

values: portal navigation p-wikibase-otherprojects p-wikibase-otherprojects-label

values:
uls-settings-trigger
Language settings
0
button
true

values:
https://cy.wikipedia.org/wiki/Odyn
Odyn – Welsh
cy
cy
interlanguage-link-target

values:
https://de.wikipedia.org/wiki/Brennofen
Brennofen – German
de
de
interlanguage-link-target

values:
https://es.wikipedia.org/wiki/Kiln
Kiln – Spanish
es
es
interlanguage-link-target

values:
https://eu.wikipedia.org/wiki/Kiln
Kiln – Basque
eu
eu
interlanguage-link-target

values:
https://fr.wikipedia.org/wiki/Touraille
Touraille – French
fr
fr
interlanguage-link-target

values:
https://ga.wikipedia.org/wiki/%C3%81ith
Áith – Irish
ga
ga
interlanguage-link-target

values: भट्टा – Hindi

values:
https://id.wikipedia.org/wiki/Tanur
Tanur – Indonesian
id
id
interlanguage-link-target

values:
https://ja.wikipedia.org/wiki/%E7%AA%AF
窯 – Japanese
ja
ja
interlanguage-link-target

values:
https://uz.wikipedia.org/wiki/Xumdon
Xumdon – Uzbek
uz
uz
interlanguage-link-target

values:
https://sco.wikipedia.org/wiki/Kil
Kil – Scots
sco
sco
interlanguage-link-target

values:
https://simple.wikipedia.org/wiki/Kiln
Kiln – Simple English
simple
simple
interlanguage-link-target

values: Промислова піч – Ukrainian

values:
https://zh.wikipedia.org/wiki/%E7%AA%91
窑 – Chinese
zh
zh
interlanguage-link-target

values: /static/images/wikimedia-button-1.5x.png 1.5x, /static/images/wikimedia-button-2x.png 2x

values: /static/images/poweredby_mediawiki_132x47.png 1.5x, /static/images/poweredby_mediawiki_176x62.png 2x

values:
suggestions
display: none; font-size: 13px;

values: mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject page-Kiln rootpage-Kiln skin-vector action-view