osmiumcontaining

Osmium-containing refers to substances that include the element osmium (Os) in elemental form, alloyed form, or as a chemical compound. Osmium is a very dense, hard transition metal in the platinum group, with an atomic number of 76. In nature it is a minor constituent of platinum-group mineral deposits and is typically obtained as a byproduct of mining nickel and platinum-group metals. Osmium can occur as elemental metal, in alloys (notably osmiridium, a hard alloy of osmium with iridium), and in several oxides and organometallic compounds such as osmium tetroxide (OsO4).

Osmium-containing materials display a range of properties. The metal itself is extremely dense and brittle, with high wear resistance in some alloys. Osmium tetroxide is volatile and highly toxic, used in electron microscopy staining to provide contrast for lipid membranes and as an oxidant in organic synthesis. In chemical synthesis, catalytic amounts of OsO4 enable dihydroxylation of alkenes to vicinal diols, often with a co-oxidant like N-methylmorpholine N-oxide (NMO). Osmium-containing catalysts and compounds appear in various oxidation and polymerization processes, and osmiridium-type alloys have been used where extreme hardness and durability are required, including some wear-resistant or specialized tooling.

Safety and handling: Due to its toxicity and volatility, OsO4 requires careful handling in fume hoods with appropriate personal protective equipment. Osmium metal and many osmium-containing salts are less hazardous, but waste should be disposed of as hazardous material. Environmental concerns center on OsO4 release and persistence.

Etymology: The name osmium derives from the Greek word osme, meaning smell, in reference to the odor of volatile osmium compounds such as OsO4.

See also: Osmium tetroxide, OsO4; osmium alloys; platinum-group metals.