Osmium compounds

Its volatility, along with its strong oxidizing power, is the origin of its quite serious toxicity - inhalation provides a very effective route for the compound to react with tissue.

[14] In biology, its property of binding to lipids has made it a widely used stain in electron microscopy.

[17] With tert-BuNH2, the imido derivative is produced: Similarly, with NH3 one obtains the nitrido complex: The [Os(N)O3]− anion is isoelectronic and isostructural with OsO4.

The suspended osmium metal can be used to catalyze hydrogenation of a wide variety of organic chemicals containing double or triple bonds.

[25] The OsF6 molecule itself (the form important for the liquid or gas phase) has octahedral molecular geometry, which has point group (Oh).

[28] This route affords the high temperature polymorph:[29] This reddish-black polymorph is orthorhombic and adopts a structure in which osmium centres are octahedrally coordinated, sharing opposite edges of the OsCl6 octahedra to form a chain.

As determined by X-ray crystallography, osmium tetrabromide is an inorganic polymer.

[33] Osmium(I) iodide is a metallic grey solid produced by the reaction of osmium tetroxide and hydroiodic acid heated in a water bath for 48 hours in a carbon dioxide atmosphere.

[35] Osmium(III) iodide is a black solid that is produced by heating hexaiodoosmic acid (H2OsI6).

[35] Osmium(IV) iodide has been claimed to exist, although the supposed way to prepare it (osmic acid, OsO2•2H2O, with hydroiodic acid[36]) produced dihydroxonium hexaiodoosmate instead of the tetraiodo compound, and instead contained mono, di and tri-iodo osmium compounds.

[37] These borides are produced in vacuum or inert atmosphere to prevent formation of osmium tetroxide, which is a hazardous compound.

[37][40] In recent methods of synthesis, it has also been found that a hexagonal phase of OsB2 exists with a similar structure to ReB2.