"doses and does not play any natural role inside the human body. Zirconium powder can cause irritation, but only contact with the eyes requires medical attention. OSHA recommendations for zirconium are 5 mg/m time weighted average limit and a 10 mg/m short-term exposure limit. Only limited data exists on the toxicology of hafnium. Group 4 element Group 4 is a group of elements in the periodic table. It contains the elements titanium (Ti), zirconium (Zr), hafnium (Hf) and rutherfordium (Rf). This group lies in the d-block of the periodic table. The group itself has not acquired a trivial name; it"
"Zirconium Zirconium is a chemical element with symbol Zr and atomic number 40. The name ""zirconium"" is taken from the name of the mineral zircon (the word is related to Persian ""zargun"" (zircon;""zar-gun"", ""gold-like"" or ""as gold"")), the most important source of zirconium. It is a lustrous, grey-white, strong transition metal that closely resembles hafnium and, to a lesser extent, titanium. Zirconium is mainly used as a refractory and opacifier, although small amounts are used as an alloying agent for its strong resistance to corrosion. Zirconium forms a variety of inorganic and organometallic compounds such as zirconium dioxide and zirconocene"
"is too long to have been observed. See list of nuclides for a tabulation. Zr is a radioisotope of zirconium with a half-life of 78.41 hours. It is produced by proton irradiation of natural yttrium-89. Its most prominent gamma photon has an energy of 909 keV. Zirconium-89 is employed in specialized diagnostic applications using positron emission tomography imaging, for example, with zirconium-89 labeled antibodies (immuno-PET). For a decay table, see Zr is a radioisotope of zirconium with a half-life of 1.53 million years, decaying with a low-energy beta particle to niobium-93, which decays with a halflife of 14 years and"
"Zinc Zinc is a chemical element with symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. In some respects zinc is chemically similar to magnesium: both elements exhibit only one normal oxidation state (+2), and the Zn and Mg ions are of similar size. Zinc is the 24th most abundant element in Earth's crust and has five stable isotopes. The most common zinc ore is sphalerite (zinc blende), a zinc sulfide mineral. The largest workable lodes are in Australia, Asia, and the United States. Zinc is refined by froth flotation of"
"the most common. It is released as a product of U, mainly in nuclear plants and during nuclear weapons tests in the 1950s and 1960s. It has a very long half-life (1.53 million years), its decay emits only low energy radiations, and it is not considered as highly hazardous. Zirconium Zirconium is a chemical element with symbol Zr and atomic number 40. The name ""zirconium"" is taken from the name of the mineral zircon (the word is related to Persian ""zargun"" (zircon;""zar-gun"", ""gold-like"" or ""as gold"")), the most important source of zirconium. It is a lustrous, grey-white, strong transition metal"
"Isotopes of zirconium Naturally occurring zirconium (Zr) is composed of four stable isotopes (of which one may in the future be found radioactive), and one very long-lived radioisotope (Zr), a primordial nuclide that decays via double beta decay with an observed half-life of 2.0×10 years; it can also undergo single beta decay, which is not yet observed, but the theoretically predicted value of t is 2.4×10 years. The second most stable radioisotope is Zr, which has a half-life of 1.53 million years. Twenty-seven other radioisotopes have been observed. All have half-lives less than a day except for Zr (64.02 days),"
"at or above mass number 93 decay by electron emission, whereas those at or below 89 decay by positron emission. The only exception is Zr, which decays by electron capture. Five isotopes of zirconium also exist as metastable isomers: Zr, Zr, Zr, Zr, Zr and Zr. Of these, Zr has the shortest half-life at 131 nanoseconds. Zr is the longest lived with a half-life of 4.161 minutes. Zirconium has a concentration of about 130 mg/kg within the Earth's crust and about 0.026 μg/L in sea water. It is not found in nature as a native metal, reflecting its intrinsic instability"
"possible symptoms. Zinc is highly toxic in parrots and poisoning can often be fatal. The consumption of fruit juices stored in galvanized cans has resulted in mass parrot poisonings with zinc. Zinc Zinc is a chemical element with symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. In some respects zinc is chemically similar to magnesium: both elements exhibit only one normal oxidation state (+2), and the Zn and Mg ions are of similar size. Zinc is the 24th most abundant element in Earth's crust and has five stable isotopes. The"
"zirconium. Very similar results were observed in hydrofluoric acid solutions. Differences in the extraction curves were interpreted as a weaker affinity for fluoride ion and the formation of the hexafluororutherfordate ion, whereas hafnium and zirconium ions complex seven or eight fluoride ions at the concentrations used: Rutherfordium Rutherfordium is a synthetic chemical element with symbol Rf and atomic number 104, named after physicist Ernest Rutherford. As a synthetic element, it is not found in nature and can only be created in a laboratory. It is radioactive; the most stable known isotope, Rf, has a half-life of approximately 1.3 hours. In"
"double beta decay (not observed experimentally) with a half-life of more than 1.10×10 years. Zr has a half-life of 2.4×10 years, and is the longest-lived radioisotope of zirconium. Of these natural isotopes, Zr is the most common, making up 51.45% of all zirconium. Zr is the least common, comprising only 2.80% of zirconium. Twenty-eight artificial isotopes of zirconium have been synthesized, ranging in atomic mass from 78 to 110. Zr is the longest-lived artificial isotope, with a half-life of 1.53×10 years. Zr, the heaviest isotope of zirconium, is the most radioactive, with an estimated half-life of 30 milliseconds. Radioactive isotopes"
"Rutherfordium Rutherfordium is a synthetic chemical element with symbol Rf and atomic number 104, named after physicist Ernest Rutherford. As a synthetic element, it is not found in nature and can only be created in a laboratory. It is radioactive; the most stable known isotope, Rf, has a half-life of approximately 1.3 hours. In the periodic table of the elements, it is a d-block element and the second of the fourth-row transition elements. It is a member of the 7th period and belongs to the group 4 elements. Chemistry experiments have confirmed that rutherfordium behaves as the heavier homologue to"
"Zr (83.4 days), and Zr (78.41 hours). The primary decay mode is electron capture for isotopes lighter than Zr, and the primary mode for heavier isotopes is beta decay. Zirconium is the heaviest element that can be formed from symmetric fusion, from either Sc, or Ca producing Zr (after two beta-plus decays from Mo) and Zr respectively. All heavier elements are formed either through asymmetric fusion or during the collapse of supernovae. As most of these are energy-absorbing processes, most nuclides of elements heavier than zirconium are theoretically unstable to spontaneous fission, although in many cases, the half-life for this"
"Group 12 element Group 12, by modern IUPAC numbering, is a group of chemical elements in the periodic table. It includes zinc (Zn), cadmium (Cd) and mercury (Hg). The further inclusion of copernicium (Cn) in group 12 is supported by recent experiments on individual copernicium atoms. Formerly this group was named ""IIB"" (pronounced as ""group two B"", as the ""II"" is a Roman numeral) by CAS and old IUPAC system. The three group 12 elements that occur naturally are zinc, cadmium and mercury. They are all widely used in electric and electronic applications, as well as in various alloys. The"
"the Zr(ClO) molecule has a D symmetry with eightfold square antiprism oxygen coordination. Each perchorate group is bidentate. The chlorine atoms are in a tetrahedral arrangement around the central zirconium. In the solid phase, Zr(ClO) crystals are monoclinic with a=12.899, b=13.188, c=7.937 Å, β=107.91°. There are four molecules per unit cell. Double salts of zirconium perchlorate are called perchloratozirconates or hexaperchloratozirconates. Known salts include caesium perchloratozirconate (CsZr(ClO)), and nitrile perchloratozirconate(sic) ((NO)Zr(ClO)). Other perchloratozirconates with varying numbers of perchlorate groups also include CsZr(ClO), CsZr(ClO), and CsZr(ClO). Zirconyl perchlorate (CAS: 15607-09-7) is another perchlorate of zirconium with the formula ZrO(ClO). It is"
"ZrOCl·8HO was found to be the chloride salt of a tetrameric cation [Zr(OH)(HO)] in which there is a square of Zr ions with two hydroxide groups bridging between Zr atoms on each side of the square and with four water molecules attached to each Zr atom. The mineral malachite is a typical example of a basic carbonate. The formula, CuCO(OH) shows that it is halfway between copper carbonate and copper hydroxide. Indeed, in the past the formula was written as CuCO·Cu(OH). The crystal structure is made up of copper, carbonate and hydroxide ions. The mineral atacamite is an example of"
"fewer Zr(III) compounds are known, and Zr(II) is very rare. The most common oxide is zirconium dioxide, ZrO, also known as ""zirconia"". This clear to white-coloured solid has exceptional fracture toughness and chemical resistance, especially in its cubic form. These properties make zirconia useful as a thermal barrier coating, although it is also a common diamond substitute. Zirconium monoxide, ZrO, is also known and S-type stars are recognised by detection of its emission lines in the visual spectrum. Zirconium tungstate has the unusual property of shrinking in all dimensions when heated, whereas most other substances expand when heated. Zirconyl chloride"
"Zirconium perchlorate Zirconium perchlorate is a molecular substance containing zirconium and perchlorate groups with formula Zr(ClO). Zr(ClO) is a volatile crystalline product. It can be formed by reacting zirconium tetrachloride with dry perchloric acid at liquid nitrogen temperatures. Zr(ClO) sublimes slowly in a vacuum at 70°C showing that the molecule is covalently bound rather than being ionic. The reaction also forms some zirconyl perchlorate (or zirconium oxyperchlorate) ZrO(ClO) as even apparently pure perchloric acid is in equilibrium with dichlorine heptoxide, hydronium ions and perchlorate ions. This side product can be minimised by adding more dichlorine heptoxide or doing the reaction"
"Zircon Zircon ( or ) is a mineral belonging to the group of nesosilicates. Its chemical name is zirconium silicate, and its corresponding chemical formula is ZrSiO. A common empirical formula showing some of the range of substitution in zircon is (Zr, REE)(SiO)(OH). Zircon forms in silicate melts with large proportions of high field strength incompatible elements. For example, hafnium is almost always present in quantities ranging from 1 to 4%. The crystal structure of zircon is tetragonal crystal system. The natural color of zircon varies between colorless, yellow-golden, red, brown, blue and green. Colorless specimens that show gem quality"
"Anders Gustaf Ekeberg named the new oxide ""yttria"". Elemental yttrium was first isolated in 1828 by Friedrich Wöhler. The most important use of yttrium is in making phosphors, such as the red ones used in television set cathode ray tube (CRT) displays and in LEDs. Other uses include the production of electrodes, electrolytes, electronic filters, lasers and superconductors; various medical applications; and as traces in various materials to enhance their properties. Yttrium has no known biological role, and exposure to yttrium compounds can cause lung disease in humans. Zirconium is a chemical element with the symbol Zr and atomic number"
"arises. Materials fabricated from zirconium metal and ZrO are used in space vehicles where resistance to heat is needed. High temperature parts such as combustors, blades, and vanes in jet engines and stationary gas turbines are increasingly being protected by thin ceramic layers, usually composed of a mixture of zirconia and yttria. The isotope Zr has been applied to the tracking and quantification of molecular antibodies with positron emission tomography (PET) cameras (a method called ""immuno-PET""). Immuno-PET has reached a maturity of technical development and is now entering the phase of wide-scale clinical applications. Until recently, radiolabeling with Zr was"
"Compounds of zinc Compounds of zinc are chemical compounds containing the element zinc which is a member of the group 12 of the periodic table. The oxidation state of most compounds is the group oxidation state of +2. Zinc may be classified as a post-transition main group element with zinc(II). Zinc compounds are noteworthy for their nondescript behavior, they are generally colorless, do not readily engage in redox reactions, and generally adopt symmetrical structures. In its compounds, Zn ions have an electronic configuration [Ar]3d. As such, its complexes tend to be symmetrical, ZnO and zinc sulfide, ZnS, (zincblende) in which"
"Zirconium acetylacetonate Zirconium acetylacetonate is the coordination complex with the formula Zr(CHO). It is a common acetylacetonate of zirconium. It is a white solid that exhibits high solubility in nonpolar organic solvents, but not simple hydrocarbons. The complex is prepared by treating zirconium oxychloride with acetylacetone: The complex has a square antiprismatic geometry with eight nearly equivalent Zr-O bonds of length 2.19 Å. The molecular symmetry is D, i.e. the complex is chiral. Compounds of high coordination number tend to be stereochemically nonrigid as indicated by the observation of one methyl signal by proton NMR spectroscopy. More volatile than Zr(acac)"
"about 5.8 ppm of the Earth's upper crust by mass. It does not exist as a free element on Earth, but is found combined in solid solution with zirconium in natural zirconium compounds such as zircon, ZrSiO, which usually has about 1–4% of the Zr replaced by Hf. Rarely, the Hf/Zr ratio increases during crystallization to give the isostructural mineral hafnon (Hf,Zr)SiO, with atomic Hf > Zr. An obsolete name for a variety of zircon containing unusually high Hf content is ""alvite"". A major source of zircon (and hence hafnium) ores is heavy mineral sands ore deposits, pegmatites, particularly in"
"the solid state, featuring octahedral Zr centers. Zirconium(IV) bromide Zirconium(IV) bromide is the inorganic compound with the formula ZrBr. This colourless solid is the principal precursor to other Zr–Br compounds. ZrBr is prepared by the action of bromine on zirconium oxide via a carbothermic reaction: Like many related tetrahalides, it is purified by sublimation. Like related tetrabromides of Ti and Hf, ZrBr hydrolyzes readily to give oxy-bromide, with release of hydrogen bromide. No single crystal X-ray study of ZrBr has been described. Some reports suggest that it is isostructural with TiCl and TiBr, featuring tetrahedral metal centers. Other studies indicate"
"Strontium Strontium is the chemical element with symbol Sr and atomic number 38. An alkaline earth metal, strontium is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is exposed to air. Strontium has physical and chemical properties similar to those of its two vertical neighbors in the periodic table, calcium and barium. It occurs naturally mainly in the minerals celestine and strontianite, and is mostly mined from these. While natural strontium is stable, the synthetic Sr isotope is radioactive and is one of the most dangerous components of"
"neutron capture cross section of 0.7 barns. Most fission zirconium consists of other isotopes; the other isotope with a significant neutron absorption cross section is Zr with a cross section of 1.24 barns. Zr is a less attractive candidate for disposal by nuclear transmutation than are Tc and I. Mobility in soil is relatively low, so that geological disposal may be an adequate solution. Isotopes of zirconium Naturally occurring zirconium (Zr) is composed of four stable isotopes (of which one may in the future be found radioactive), and one very long-lived radioisotope (Zr), a primordial nuclide that decays via double"
"reactors.) Zirconium tetrafluoride Zirconium(IV) fluoride (ZrF) is an inorganic chemical compound. It is a component of ZBLAN fluoride glass. It is insoluble in water. It is the main component of fluorozirconate glasses. Three crystalline phases of ZrF have been reported, α (monoclinic), β (tetragonal, Pearson symbol tP40, space group P42/m, No 84) and γ (unknown structure). β and γ phases are unstable and irreversibly transform into the α phase at 400 °C. Zirconium fluoride is used as a zirconium source in oxygen-sensitive applications, e.g. metal production. Zirconium fluoride can be purified by distillation or sublimation. Conditions/substances to avoid are: moisture,"
"was seen as containing 118 neutrons rather than 118 nuclear electrons, and its positive charge now was realized to come entirely from a content of 79 protons. After 1932, therefore, an element's atomic number ""Z"" was also realized to be identical to the proton number of its nuclei. The conventional symbol ""Z"" possibly comes from the German word (atomic number). However, prior to 1915, the word ""Zahl"" (simply ""number"") was used for an element's assigned number in the periodic table. Each element has a specific set of chemical properties as a consequence of the number of electrons present in the"
"Copernicium Copernicium is a synthetic chemical element with symbol Cn and atomic number 112. It is an extremely radioactive element, and can only be created in a laboratory. The most stable known isotope, copernicium-285, has a half-life of approximately 29 seconds. Copernicium was first created in 1996 by the GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany. It is named after the astronomer Nicolaus Copernicus. In the periodic table of the elements, copernicium is a d-block transactinide element and a group 12 element. During reactions with gold, it has been shown to be an extremely volatile metal, so"
"low temperature, and does not contaminate the surface with other elements such as hydrogen or fluorine. Zirconium nitrate Zirconium nitrate is a volatile anhydrous transition metal nitrate of zirconium with formula Zr(NO). It has alternate names of zirconium tetranitrate, or zirconium(IV) nitrate. It has a UN number of UN 2728 and is class 5.1, meaning oxidising substance. Anhydrous Zirconium nitrate can be made from zirconium tetrachloride reacting with dinitrogen pentoxide. ZrCl + 4 NO → Zr(NO) + 4ClNO The product can be purified by sublimation in a vacuum. A contaminating substance in this is nitronium pentanitratozirconate. (NO)Zr(NO). Zirconium nitrate pentahydrate"
"which produces an isotope of gallium. Zinc has an electron configuration of [Ar]3d4s and is a member of the group 12 of the periodic table. It is a moderately reactive metal and strong reducing agent. The surface of the pure metal tarnishes quickly, eventually forming a protective passivating layer of the basic zinc carbonate, , by reaction with atmospheric carbon dioxide. This layer helps prevent further reaction with air and water. Zinc burns in air with a bright bluish-green flame, giving off fumes of zinc oxide. Zinc reacts readily with acids, alkalis and other non-metals. Extremely pure zinc reacts only"
"periodic table are influenced by the lanthanide contraction. The radii of the period-6 transition metals are smaller than would be expected if there were no lanthanides, and are in fact very similar to the radii of the period-5 transition metals, since the effect of the additional electron shell is almost entirely offset by the lanthanide contraction. For example, the atomic radius of the metal zirconium, Zr, (a period-5 transition element) is 159 pm and that of hafnium, Hf, (the corresponding period-6 element) is 156 pm. The ionic radius of Zr is 79 pm and that of Hf is 78 pm."
"Zirconium tetrafluoride Zirconium(IV) fluoride (ZrF) is an inorganic chemical compound. It is a component of ZBLAN fluoride glass. It is insoluble in water. It is the main component of fluorozirconate glasses. Three crystalline phases of ZrF have been reported, α (monoclinic), β (tetragonal, Pearson symbol tP40, space group P42/m, No 84) and γ (unknown structure). β and γ phases are unstable and irreversibly transform into the α phase at 400 °C. Zirconium fluoride is used as a zirconium source in oxygen-sensitive applications, e.g. metal production. Zirconium fluoride can be purified by distillation or sublimation. Conditions/substances to avoid are: moisture, active"