Osmium is a metallic chemical element in the platinum family. This element is quite rare, and it tends to be rather expensive as a result, making commercial applications for it rather limited. The metal tends to be used mostly in alloys, often in very small amounts to make metal stronger and durable without driving up the cost too much. Most of the world's supply is found in Turkey and Bulgaria, although it appears in small amounts in other regions as well; the element rarely appears in a pure form, but is combined with other metals in the form of ores.
When osmium is isolated, it is an extremely hard silvery metal with a slightly blue cast and a hexagonal crystalline structure that is very tightly packed, making it an extremely dense element. It is among the heaviest of elements, along with iridium, a close neighbor on the periodic table. The atomic number of osmium is 76, and the metal is identified with the symbol Os on the periodic table. This element is also present in an assortment of compounds, including osmium tetroxide, a toxic compound with a number of uses in the sciences.
Credit for the discovery of osmium is generally given to the English chemists Smithson Tennant and William Hyde Wollaston. The two men were working with platinum, attempting to purify the metal, in 1803 when they isolated two distinctive and unfamiliar elements, which turned out to be osmium and iridium. They officially published their findings in 1804, naming the element for the Greek osme, “a smell,” after the distinctive odor of the compounded form.
Because this element is so rare, its expense has made it prohibitive to work with and few uses have been developed for it. It is used in an alloyed form in things like nibs for fountain pens, electrical contacts, and medical devices, since it makes metals much stronger. One compound is used in fingerprint detection, and osmium tetroxide is used in chemistry and biology research labs. The element was also once used in light bulbs, although this was rare since other elements like tungsten are easier to work with, cheaper, and more effective.
This element itself is not toxic, although osmium tetroxide is extremely poisonous. Like other elements, its particles can cause damage to the mucus membranes because they act as an irritant. Prolonged exposure to the dust can damage the lungs; people who participate in any activity with this element that generates dust should wear a mask.