Ammonium hexachloroosmate(IV) is an inorganic

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with the chemical formula .

Synthesis

Ammonium hexachloroosmate(IV) can be produced by the reduction of

osmium tetroxide Osmium tetroxide (also osmium(VIII) oxide) is the chemical compound with the formula OsO4. The compound is noteworthy for its many uses, despite its toxicity and the rarity of osmium. It also has a number of unusual properties, one being that the ...

potassium osmate Potassium osmate is the inorganic compound with the formula K2 sO2(OH)4 This diamagnetic purple salt contains osmium in the VI (6+) oxidation state. When dissolved in water a red solution is formed. When dissolved in dilute alcohols, the salt give ...

with iron dichloride in

hydrochloric acid Hydrochloric acid, also known as muriatic acid or spirits of salt, is an aqueous solution of hydrogen chloride (HCl). It is a colorless solution with a distinctive pungency, pungent smell. It is classified as a acid strength, strong acid. It is ...

in the presence of

ammonium ion Ammonium is a modified form of ammonia that has an extra hydrogen atom. It is a positively charged (cationic) molecular ion with the chemical formula or . It is formed by the addition of a proton (a hydrogen nucleus) to ammonia (). Ammonium ...

s: : : + + 2 + + 4 + 2KCl 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(IV) forms dark red crystals of the

cubic system In crystallography, the cubic (or isometric) crystal system is a crystal system where the unit cell is in the shape of a cube. This is one of the most common and simplest shapes found in crystals and minerals. There are three main varieties of ...

space group In mathematics, physics and chemistry, a space group is the symmetry group of a repeating pattern in space, usually in three dimensions. The elements of a space group (its symmetry operations) are the rigid transformations of the pattern that ...

''Fm''3''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 Osmium () is a chemical element; it has Symbol (chemistry), symbol Os and atomic number 76. It is a hard, brittle, bluish-white transition metal in the platinum group that is found as a Abundance of elements in Earth's crust, trace element in a ...

: :: :: Similar to sodium hexachloroosmate, ammonium hexachloroosmate decomposes to

osmium dioxide Osmium dioxide is an inorganic compound with the formula . It exists as brown to black crystalline powder, but single crystals are golden and exhibit metallic conductivity. The compound crystallizes in the rutile structural motif, i.e. the connec ...

when exposed to strong alkali, and reacts with ammonia to produce

osmium diammine hydroxide Osmium diammine hydroxide (also known as osmium oxydiammine dihydroxide) is a proposed inorganic chemical compound with the formula . It exists as a brown powder that is insoluble in water. The compound is claimed to be produced by reducing osmi ...

, . Ammonium hexachloroosmate is stable in hydrochloric acid, but it is oxidized by nitric acid, forming osmium tetroxide.

Reactions

Ammonium hexachloroosmate reacts with

triphenylphosphine Triphenylphosphine (IUPAC name: triphenylphosphane) is a common organophosphorus compound with the formula P(C6H5)3 and often abbreviated to P Ph3 or Ph3P. It is versatile compound that is widely used as a reagent in organic synthesis and as a l ...

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.

Uses

The compound is used as a pharmaceutical, organic, and chemical intermediate.

References

{{ammonium salts Chloro complexes Ammonium compounds Chlorometallates Osmium compounds