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 °C.^[1]

Sodium hexachloroplatinate

Structure of sodium hexachloroplatinate(IV)
Sample of sodium hexachloroplatinate(IV)
Names
Other names Sodium chloroplatinate Disodium platinum hexachloride
Identifiers
CAS Number	16923-58-3 Y
3D model (JSmol)	Interactive image
ChemSpider	9309311
ECHA InfoCard	100.037.242
EC Number	240-983-5
PubChem CID	11134193
UNII	Q7589P090H Y
CompTox Dashboard (EPA)	DTXSID00893459
InChI Key: QGFSULIVEYGQQY-UHFFFAOYSA-H InChI=1S/6ClH.2Na.Pt/h6*1H;;;/q;;;;;;2*+1;+4/p-6
SMILES [Na+].[Na+].Cl[Pt-2](Cl)(Cl)(Cl)(Cl)Cl
Properties
Chemical formula	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)
Solubility in water	Soluble
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H300, H301, H317, H318, H334
Precautionary statements	P261, P264, P270, P272, P280, P285, P301+P310, P302+P352, P304+P341, P305+P351+P338, P310, P321, P330, P333+P313, P342+P311, P363, P405, P501
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

The compound is utilised as the most common chemical shift reference in platinum-195 NMR spectroscopy, relative to which the shifts of other platinum species in solution are reported.^[2]

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.^[3]

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

H₂[PtCl₆] + 2 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

This compound also reacts with a base, such as sodium hydroxide, producing [Pt(OH)₆]⁻² ion.^[4]

Applications

A 1.2 M solution of sodium hexachloroplatinate in D₂O is the most commonly chosen reference compound for chemical shifts in ¹⁹⁵Pt NMR. The salt is chosen as it is commercially available at a lower price relative to other platinum compounds, and it possesses high solubility enabling quick acquisition of spectra.^[2]