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Iridium: Platinum
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Iridium is one of the six platinum group elements and is one of rarest elements found on earth. The biological values of Iridium, and other members of the platinum group of elements, are just now beginning to be realized thanks to breakthroughs in high-temp chemical analysis techniques. Forms of Iridium, and its twin Rhodium, are now thought by some researchers to account for some 5% or more of the dry weight of the brain. They apparently perform essential tasks as superconductors in a sort of nutrient-of-consciousness role.
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Iridium is a metallic element. It is a dense, very hard, brittle, silvery-white transition metal of the platinum group. The metal is used in high strength alloys that can withstand high temperatures and occurs in natural alloys with platinum or osmium. Iridium is notable for being the most corrosion resistant element known and for its significance in the determination of the probable cause of the demise, by a meteorite strike, of the dinosaurs. It is used in high temperature apparati, electrical contacts, and as a hardening agent for platinum.
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Iridium was discovered in 1803 by British scientist Smithson Tennant in London, England along with osmium in the dark-coloured residue of dissolving crude platinum in aqua regia (a mixture of hydrochloric and nitric acid). The element was named after the Greek word for rainbow (ίρις, iris; iridium means "of rainbows") because many of its salts are strongly coloured.
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Iridium and osmium were discovered at the same time by the British chemist Smithson Tennant in 1803. Iridium and osmium were identified in the black residue remaining after dissolving platinum ore with aqua regia, a mixture of 25% nitric acid (HNO3) and 75% hydrochloric acid (HCl). Today, iridium is still obtained from platinum ores and as a by-product of mining nickel.
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Iridium is a chemical element in the periodic table that has the symbol Ir and atomic number 77. A dense, very hard, brittle, silvery-white transition metal of the platinum family, iridium is used in high strength alloys that can withstand high temperatures and occurs in natural alloys with platinum or osmium. Iridium is notable for being the most corrosion resistant element known and for its association with the demise of the dinosaurs, in the form of a meteorite strike. It is used in high temperature apparatus, electrical contacts, and as a hardening agent for platinum.
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Osmium and Iridium are the two most dense elements in pure form. They are ... very pretty metals, iridium particularly. Unlike osmium, iridium does not tarnish in air, and is in fact impervious to many forms of chemical attack, much like platinum. An alloy of 90% platinum and 10% iridium is widely used in both the jewelry and chemical industries, because it is strong, hard, beautiful, and impervious to almost all chemicals even at very high temperatures.
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