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 Kepert model cannot explain the formation of square planar complexes or distorted structures.
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. Educ., 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. doi:10.1126/science.173.4003.1238. ISSN 0036-8075. PMID 17775218.
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. doi:10.1126/science.1102209. PMID 15375262. [permanent dead link]
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=821618453"
Categories:
Chemistry theories
Molecular geometry
Stereochemistry
Quantum chemistry
Hidden categories:
CS1 uses Japanese-language script (ja)
CS1 Japanese-language sources (ja)
All articles with dead external links
Articles with dead external links from December 2017
Articles with permanently dead external links
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 21 January 2018, at 16:17.
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

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: img

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

attrs: href class

attrs: href class title

attrs: class style

value: b

attrs: href title

value: sup

value: i

values:
/wiki/Bakerian_Lecture
mw-redirect
Bakerian Lecture

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

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
//doi.org/10.1126%2Fscience.1102209

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

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: nowraplinks collapsible autocollapse navbox-inner

values:
nofollow
external text
https://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 dead external links

values: Category:Articles with dead external links from December 2017

values: Category:Articles with permanently dead external links

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

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: 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:
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