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Iridium is a chemical element; it has symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum group, it is considered the second-densest naturally occurring metal (after osmium) with a density of 22.56 g/cm 3 (0.815 lb/cu in) [8] as defined by experimental X-ray crystallography. [a] 191 Ir and 193 Ir ...
Isotopes of iridium (77Ir) There are two natural isotopes of iridium (77 Ir), and 37 radioisotopes, the most stable radioisotope being 192 Ir with a half-life of 73.83 days, and many nuclear isomers, the most stable of which is 192m2 Ir with a half-life of 241 years. All other isomers have half-lives under a year, most under a day.
Platinum–iridium alloy. The international prototype of the kilogram (IPK) is an artifact standard of platinum–iridium alloy that was defined as having a mass of exactly one kilogram. Platinum–iridium alloys are alloys of the platinum group precious metals platinum and iridium. Typical alloy proportions are 90:10 or 70:30 (Pt:Ir).
They have similar physical and chemical properties, and tend to occur together in the same mineral deposits. [2] However, they can be further subdivided into the iridium-group platinum-group elements (IPGEs: Os, Ir, Ru) and the palladium-group platinum-group elements (PPGEs: Rh, Pt, Pd) based on their behaviour in geological systems. [3]
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A noble metal is ordinarily regarded as a metallic element that is generally resistant to corrosion and is usually found in nature in its raw form. Gold, platinum, and the other platinum group metals (ruthenium, rhodium, palladium, osmium, iridium) are most often so classified. Silver, copper, and mercury are sometimes included as noble metals ...
synthetic element. Group 9, by modern IUPAC numbering, [1] is a group (column) of chemical elements in the d-block of the periodic table. Members of Group 9 include cobalt (Co), rhodium (Rh), iridium (Ir) and meitnerium (Mt). [2] These elements are among the rarest of the transition metals. [3] Like other groups, the members of this family show ...
Well-characterized compounds containing iridium in the +6 oxidation state include IrF6 and the oxides Sr2MgIrO6 and Sr2CaIrO6. [2][3] iridium (VIII) oxide (IrO4) was generated under matrix isolation conditions at 6 K in argon. [4] The highest oxidation state (+9), which is also the highest recorded for any element, is found in gaseous [IrO4]+.