Sodium hexachloroplatinate

Sodium hexachloroplatinate(IV), the sodium salt of chloroplatinic acid, is an inorganic compound with the formula Na2[PtCl6], consisting of the sodium cation and the hexachloroplatinate anion. As explained by Cox and Peters, anhydrous sodium hexachloroplatinate, which is yellow, tends to form the orange hexahydrate upon storage in humid air. The latter can be dehydrated upon heating at 110 ºC.[1]

Sodium hexachloroplatinate
Names
Other names
Sodium chloroplatinate
Disodium platinum hexachloride
Identifiers
3D model (JSmol)
ECHA InfoCard 100.037.242
UNII
Properties
Na2PtCl6
Molar mass 453.7742 g/mol (anhydrous)
561.86588 g/mol (hexahydrate)
Appearance Orange crystalline solid
Density 2.5 g/cm³
Melting point 110 °C (230 °F; 383 K)
Soluble
Hazards
Toxic (T)
R-phrases (outdated) R25, R41, R42/43
S-phrases (outdated) S22, S24, S26, S36/37/39, S45
Related compounds
Other anions
 Sodium hexafluorophosphate
Sodium hexafluoroaluminate
Other cations
 Potassium hexachloroplatinate
Ammonium hexachloroplatinate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Preparation and reactions

Sodium hexachloroplatinate is obtained as an intermediate in the preparation of Pt complexes, often starting with the dissolution of platinum in aqua regia, giving hexachloroplatinic acid, which is then reacted with sodium chloride and evaporated, leaving the salt behind.[2]

Pt + 4 HNO3 + 6 HCl → H2[PtCl6] + 4 NO2 + 4 H2O
H2[PtCl6] + NaCl → Na2[PtCl6] + 2 HCl

The compound can be converted back to platinum metal via conversion to the ammonium salt followed by thermal decomposition, allowing platinum metal to be recovered from laboratory residues.

Na2[PtCl6] + 2 NH4Cl → (NH4)2[PtCl6] + 2 NaCl
3 (NH4)2[PtCl6] → 3 Pt + 2 N2 + 2 NH4Cl + 16 HCl

Reference
  1. Cox, Lawrence E.; Peters, Dennis G. (1972). Disodium Hexachloroplatinate(IV). Inorganic Syntheses. pp. 173–176. doi:10.1002/9780470132449.ch34. ISBN 9780470132449.
  2. Kauffman, George B.; Teter, Larry A. (1963). Recovery of Platinum from Laboratory Residues. Inorganic Syntheses. 7. pp. 232–236. doi:10.1002/9780470132388.ch61. ISBN 9780470132388.
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