The compound osmium tetroxide is very toxic but has a number of important uses.
Osmium alloys such as osmiridium are very hard and are used in high-wear applications and electrical contacts.
Osmium is quite valuable, costing about US $100 per gram (g).
Turkey has the world's largest known reserve of osmium, estimated at 127,000 tons.
Osmium also occurs in nickel-bearing ores found in the Sudbury, Ontario region, with other platinum group metals.
After a few years, however, osmium was replaced by the more stable metal tungsten.
Osmium (from the Greek word osme, meaning "a smell") was discovered in 1803 by Smithson Tennant, while working with William Hyde Wollaston in London, England.
Osmium is a transition metal that lies between rhenium and iridium in period 6 of the periodic table.
In 1898, Austrian chemist Carl Auer von Welsbach developed the "Oslamp," with a filament made of osmium, which he introduced commercially in 1902.
Osmium has seven naturally occurring isotopes, five of which are stable: 187Os, 188Os, 189Os, 190Os, and (most abundant) 192Os.
Osmium (chemical symbol Os, atomic number 76) is a hard, brittle, blue-gray or blue-black transition metal in the platinum family and is found as an alloy in platinum ore.
Osmium tetroxide, despite being very toxic, has been used for a number applications, including fingerprint detection and staining fatty tissue for microscope slides.
Osmium has the highest melting point and the lowest vapor pressure of the platinum family.
The most notable application of osmium in dating has been in conjunction with iridium, to analyze the layer of shocked quartz along the "K-T boundary."
Osmium is therefore often listed as the densest element known.
Common oxidation states of osmium are +4 and +3, but observed oxidation states range from +1 to +8.
An alloy of 90 percent platinum and 10 percent osmium is used in surgical implants such as pacemakers and replacement pulmonary valves.
The measured density of osmium is higher than that of any other element, with a value slightly higher than that of iridium.