Ammonium hexachloroosmate(IV)
Ammonium hexachloroosmate is an inorganic chemical compound with the chemical formula.
Synthesis
Ammonium hexachloroosmate can be produced by the reduction of osmium tetroxide or potassium osmate with iron dichloride in hydrochloric acid in the presence of ammonium ions:It can also be prepared by addition of an ammonium chloride solution to hexachloroosmic acid, or by addition of ammonium chloride to a solution of sodium hexachloroosmate.
Physical properties
Ammonium hexachloroosmate forms dark red crystals of the cubic system, space group Fm3''m'', cell parameters a = 0.9729 nm, Z = 4.It is poorly soluble in cold water.
Chemical properties
The compound is reduced by hydrogen to metallic osmium:When exposed to strong alkali, ammonium hexachloroosmate reacts to produce osmium oxydiammine dihydroxide,.
Ammonium hexachloroosmate is stable in hydrochloric acid, but it is oxidized by nitric acid, forming osmium tetroxide.
Reactions
Ammonium hexachloroosmate reacts with triphenylphosphine to form various complexes in which osmium is divalent.+ 4 + 2 + 2
+ 6 + 2 + 3
It also reacts with triphenylphosphine in a solution of t-butyl alcohol and water to produce.
When ammonium hexachloroosmate is refluxed with diethylphenylphosphine, is formed.