Tennant named the element iridium after the Latin word “iris,” meaning rainbow, since the salts he examined were highly colorful. Treating the residue with alkalis and acids, he was able to extract iridium while simultaneously discovering osmium. This paperdescribes investigations carried out to determine the metal losses from polycrystalline iridium discs, by means of a. The black residue left behind was commonly thought to be graphite before Tennant investigated further. Iridium reacts with oxygen at high temperatures forming volatile oxides, the evaporation of which considerably increases the iridium losses in oxygen-containing atmospheres, when compared with high-vacuum conditions. Iridium was first discovered in 1803 by English chemist Smithson Tennant when he examined the residue left over when crude platinum was dissolved in Aqua Regia (a mixture of nitric and hydrochloric acids). Iridium in its powder form is a known irritant and fire hazard with low toxicity. 2), which defined the standard for the metric system until 1960. Due to iridium’s high corrosion resistance, an alloy of 90% platinum and 10% iridium was used to create the standard meter bar (Fig.
Iridium resists chemical attack by acids but is susceptible to attack by molten salts such as sodium chloride (NaCl) and sodium cyanide (NaCN). Due to its extreme hardness and brittle properties, iridium is. noble metal, any of several metallic chemical elements that have outstanding resistance to oxidation, even at high temperatures the grouping is not strictly defined but usually is considered to include rhenium, ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, and gold i.e. Both metals are used together in electrode coatings able to withstand the very. Four car iridium spark plug isolated over white background. Iridium and ruthenium are used together in several industrial chemical.
It is almost as unreactive as gold and extremely rare in nature. A platinum group metal, iridium is white, resembling platinum, but with a slight yellowish cast. Iridium is a metallic chemical element belonging to the class of transition metals, silver. 1) that is the most corrosion-resistant metal known to man.
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