Ammonium hexachloroplatinate

Ammonium hexachloroplatinate

IUPAC name	Ammonium hexachloroplatinate(IV)
Identifiers
CAS number	16919-58-7
Properties
Molecular formula	(NH₄)₂PtCl₆
Molar mass	443.87 g/mol
Density	3.07 g/cm³
Melting point	°C
Solubility in other solvents	0.5 g/100 mL (20 °C) 3.365 g/100 mL (100 °C)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Ammonium hexachloroplatinate, also known as ammonium chloroplatinate, is an inorganic compound with the formula (NH₄)₂PtCl₆. It is a rare example of a soluble platinum(IV) salt that is not hygroscopic. It forms intensely yellow solutions in water. In the presence of 1M NH₄Cl, its solubility is only 0.0028g/100 mL.

Additional recommended knowledge

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Preparation and structure

The compound consists of separate ammonium cations and octahedral [PtCl₆]^2- anions. It is usually generated by treating a solution of chloroplatinic acid with a solution of an ammonium salt.^[1] The fine yellow salt precipitates. The complex is so poorly soluble that this step is employed in the isolation of platinum from ores and recycled residues.^[2]

Uses and reactions

This yellow powder is used in platinum plating.

Heating (NH₄)₂PtCl₆ under a stream of hydrogen at 200 °C produces platinum sponge. Treatment with chlorine gives H₂PtCl₆.^[1]

References

^ ^a ^b Kauffman, G. B. "Ammonium Hexachloroplatinate" Inorganic Syntheses McGraw-Hill: New York, 1967, IX, pages 182-4.
^ Cotton, S. A. Chemistry of Precious Metals, Chapman and Hall (London): 1997. ISBN 0-7514-0413-6.

Categories: Platinum compounds | Ammonium compounds