Potassium tetrachloroplatinate

Potassium tetrachloroplatinate(II) is the chemical compound with the formula K₂PtCl₄. This reddish orange salt is an important reagent for the preparation of other coordination complexes of platinum. It consists of potassium cations and the square planar dianion PtCl2−4. Related salts are also known including Na₂PtCl₄, which is brown-colored and soluble in alcohols, and quaternary ammonium salts, which are soluble in a broader range of organic solvents.

Potassium tetrachloroplatinate

Names
IUPAC name Potassium tetrachloridoplatinate(2–)
Other names Potassium chloroplatinite
Identifiers
CAS Number	10025-99-7 Y
3D model (JSmol)	Interactive image
ChemSpider	55364 Y
ECHA InfoCard	100.030.034
EC Number	233-050-9
PubChem CID	61440
UNII	B74O00UCWC N
CompTox Dashboard (EPA)	DTXSID10904020
InChI InChI=1S/4ClH.2K.Pt/h4*1H;;;/q;;;;2*+1;+2/p-4 Y Key: RVRDLMCWUILSAH-UHFFFAOYSA-J Y InChI=1/4ClH.2K.Pt/h4*1H;;;/q;;;;2*+1;+2/p-4/rCl4Pt.2K/c1-5(2,3)4;;/q-2;2*+1 Key: RVRDLMCWUILSAH-SSOJXQLRAM
SMILES [K+].[K+].Cl[Pt-2](Cl)(Cl)Cl
Properties
Chemical formula	K2PtCl4
Molar mass	415.09 g/mol
Appearance	reddish solid
Density	3.38 g/cm3
Melting point	265 °C (509 °F; 538 K)
Solubility in water	0.93 g/100 mL (16 °C) 5.3 g/100 mL (100 °C)
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H301, H315, H317, H318, H334
Precautionary statements	P261, P264, P270, P272, P280, P285, P301+P310, P302+P352, P304+P341, P305+P351+P338, P310, P321, P330, P332+P313, P333+P313, P342+P311, P362, P363, P405, P501
NFPA 704 (fire diamond)	3 0 0
Flash point	Nonflammable
Related compounds
Other anions	Potassium hexachloroplatinate
Other cations	Magnus's green salt Sodium chloroplatinate
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

Potassium tetrachloroplatinate is prepared by reduction of the corresponding hexachloroplatinate salt with sulfur dioxide.^[1] K₂PtCl₄ is one of the salts that is most easily obtained from platinum ores. The complex is appreciably soluble only in water. Treatment with alcohols, especially in the presence of base, causes reduction to platinum metal. Organic tetrachloroplatinate salts, such as [PPN]₂PtCl₄ are soluble in chlorocarbons.^[2]

Reactions

The chloride ligands on [PtCl₄]²⁻ are displaced by many other ligands. Upon reaction with triphenylphosphine, [PtCl₄]²⁻ converts to cis-bis(triphenylphosphine)platinum chloride:

PtCl₄²⁻ + 2 PPh₃ → cis-PtCl₂(PPh₃)₂ + 2 Cl⁻

The anti-cancer drug Cisplatin can similarly be prepared:^[1]

PtCl₄²⁻ + 2 NH₃ → cis-PtCl₂(NH₃)₂ + 2 Cl⁻

Enedithiolates displace all four chloride ligands to give bis(dithiolene) complexes.^[3] Reduction gives colloidal platinum of potential interest for catalysis.^[4]

Historically, an important reaction involves ammonia and [PtCl₄]²⁻. This reaction affords a deep green precipitate with empirical formula PtCl₂(NH₃)₂. This material, known as Magnus' green salt, is a semiconducting coordination polymer consisting of chains of alternating [PtCl₄]²⁻ and [Pt(NH₃)₄]²⁺ centres.^[5]