Chloroplatinic acid

Chloroplatinic acid

Names
IUPAC name Dihydrogen hexachloroplatinate(2–)
Other names Hexachloroplatinic acid
Identifiers
CAS Number	16941-12-1 Y
3D model (Jmol)	Interactive image
ChemSpider	55731 Y
ECHA InfoCard	100.037.267
EC Number	241-010-7
PubChem CID	61859
RTECS number	TP1510000
UNII	Q65224GJ7F Y
InChI InChI=1S/6ClH.Pt/h6*1H;/q;;;;;;+4/p-4 Y Key: GBFHNZZOZWQQPA-UHFFFAOYSA-J Y InChI=1/6ClH.Pt/h6*1H;/q;;;;;;+4/p-4/rCl6Pt/c1-7(2,3,4,5)6/q-2/p+2 Key: GBFHNZZOZWQQPA-DUMOQKOKAQ
SMILES [H+].[H+].Cl[Pt-2](Cl)(Cl)(Cl)(Cl)Cl
Properties
Chemical formula	H2PtCl6
Molar mass	409.81 g/mol
Appearance	Reddish brown solid
Density	2.431 g/cm3
Melting point	60 °C (140 °F; 333 K)
Boiling point	decomposes
Solubility in water	highly soluble
Structure
Crystal structure	Anti-fluorite.
Coordination geometry	octahedral
Dipole moment	0 D
Hazards
Safety data sheet	External MSDS
EU classification (DSD)	Toxic (T) Corrosive (C)
R-phrases	R25, R34, R42/43
S-phrases	(S1/2), S22, S26, S36/37/39, S45
NFPA 704	0 2 1
Related compounds
Other anions	Hexachloropalladic acid
Other cations	Potassium hexachloroplatinate, Ammonium hexachloroplatinate, Rubidium hexachloroplatinate, Caesium hexachloroplatinate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Chloroplatinic acid or hexachloroplatinic acid is an inorganic compound with the formula [H₃O]₂[PtCl₆](H₂O)_x. A red solid, it is an important commercial source of platinum, usually as an aqueous solution. Although often written in shorthand as H₂PtCl₆, it is the hydronium (H₃O⁺) salt of the hexachloroplatinate anion (PtCl2−
6). The compound is also available as the hexahydrate.

Chloroplatinic acid is produced by dissolving platinum metal sponge in aqua regia. Brownish red crystals can be isolated by evaporating this solution to a syrup.

A related procedure gives the hexahydrate, H₂PtCl₆(H₂O)₆.

Alternative methods have been heavily investigated, but the older literature can be unreliable.

When heated, hexachloroplatinic acid decomposes first to platinum(IV) chloride, and for this reason heating of hexachloroplatinic acid can result in insoluble platinum compounds.

Chloroplatinic acid was popularized for the determination of potassium. The potassium is selectively precipitated as potassium chloroplatinate. Determinations were done in 85% (v/v) alcohol solutions with excess platinate ions, and the precipitated product was weighed. Potassium could be detected for solutions as dilute as 0.02 to 0.2% (m/v).

This method for determination of potassium was advantageous vs. the sodium cobaltinitrite method used previously, since it required a single precipitation reaction. Today, the concentration of potassium is determined with an ion-selective electrode. These modern methods remain subject to interference.

Treatment with an ammonium salt, such as ammonium chloride, precipitates solid ammonium hexachloroplatinate,. Heating the ammonium salt in hydrogen reduces it to elemental platinum. Platinum is often isolated from ores or recycled from residues thus.