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Quercus is a platinum element. Platinum metals almost completely into elemental state, that highly dispersed in various ores, such as the original platinum mines, copper-nickel sulfide ore, a magnetic iron ore. Platinum group elements co-exist almost without exception, forming a natural alloy. In platinum-containing elemental ores, platinum is usually the main component, while the remaining platinum-based elements are small in content and must be chemically analyzed. Because osmium, iridium, palladium, rhodium and ruthenium and platinum are composed of ore, they are extracted from ore residue after platinum platinum found.
Platinum elements are chemically stable. Among them, besides platinum and palladium, they are not only insoluble in common acids, but also insoluble in aqua regia. Platinum is very soluble in aqua regia and palladium is also soluble in hot nitric acid. All platinum group elements have a strong tendency to form coordination compounds.
In 1803, the French chemist Collards Gotti and others studied the slag of platinum-based ore dissolved in aqua regia. They announced that there are two new metals in the residue that are different from platinum, which are insoluble in aqua regia. In 1804, Tynar discovered and named them. One of them was named ptenium, later changed to osmium (锇), and the element symbol was set to Os. Ptenium comes from the Greek word "evaporable", osmium comes from the Greek osme, the original meaning is "smelly". This is because the melting point of osmium tetroxide OsO 4 is only 41 ° C, which is volatile and has a foul odor. Its vapor is particularly harmful to human eyes.锇 is one of two elements capable of forming an octavalent compound in Group VIIIB of the Periodic Table of the Elements.
Earthworms are rare elements in the earth's crust (average content 0.001 g/t).
Niobium is one of the heaviest elements, second only to it, with a density of 22.61 g/cm 3 , a melting point of 3027 ° C and a boiling point of 5020 ± 100 ° C. Niobium is also the hardest metal, and its as-cast hardness is HV8000MPa, which can hardly be processed.锇 is one of the most valence elements and has a variety of ruthenium compounds. Powder bismuth is soluble in nitric acid, hot concentrated sulfuric acid, NaCIO solution and molten K 2 S 2 O 2 , etc. It is easily oxidized to form volatile OsO 4 , which has strong irritancy and toxicity.
It is rarely used alone in addition to OsO 4 as an oxidizing agent and cell stain for the oxidation of olefins and hydrazine to alcohols in organic synthesis. Its main purpose is to use a bismuth alloy as a shaft tip, a pen tip, etc., in order to exert its advantages of corrosion resistance, wear resistance and high hardness. It is also added as an alloy to improve certain properties of the alloy.
There are no independent deposits, mainly through the by-product recycling in the production process of platinum group metals. The annual output of the world is about 2 tons, mainly provided by South Africa and Russia, accounting for 47% each.
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