Platinum(IV) chloride

Platinum(IV) chloride
Names
	IUPAC name Platinum(IV) chloride
Identifiers
CAS Number	13454-96-1 ;
3D model (JSmol)	ionic monomer: Interactive image; coordination monomer: Interactive image; coordination polymer: Interactive image;
ChemSpider	19957150;
ECHA InfoCard	100.033.300
PubChem CID	26031;
UNII	W3YUG71TU2 ;
CompTox Dashboard (EPA)	DTXSID601014389 DTXSID00905309, DTXSID601014389 ;
	InChI InChI=1/4ClH.2Pt/h41H;;/q;;;;2+2/p-4 Key: KBPRWZWTZAMEIF-XBHQNQODAX;
	SMILES ionic monomer: [Pt+4].[Cl-].[Cl-].[Cl-].[Cl-]; coordination monomer: Cl[Pt](Cl)(Cl)Cl; coordination polymer: Cl[Pt-]1(Cl)(Cl)(Cl)[Cl+][Pt-2]2([Cl+]1)(Cl)(Cl)[Cl+][Pt-2]1([Cl+]2)(Cl)(Cl)[Cl+][Pt-2]2([Cl+]1)(Cl)(Cl)[Cl+][Pt-2]1([Cl+]2)(Cl)(Cl)[Cl+][Pt-2]2([Cl+]1)(Cl)(Cl)[Cl+][Pt-2]1([Cl+]2)(Cl)(Cl)[Cl+][Pt-2]2([Cl+]1)(Cl)(Cl)[Cl+][Pt-2]1([Cl+]2)(Cl)(Cl)[Cl+][Pt-]([Cl+]1)(Cl)(Cl)(Cl)Cl;
Properties
Chemical formula	PtCl4
Molar mass	336.89 g/mol
Appearance	brown-red powder
Density	4.303 g/cm3 (anhydrous) ; 2.43 g/cm3 (pentahydrate)
Melting point	370 °C (698 °F; 643 K) decomposes
Boiling point	decomposes
Solubility in water	58.7 g/100 mL (anhydrous) ; very soluble (pentahydrate)
Solubility	anhydrous ; soluble in acetone ; slightly soluble in ethanol ; insoluble in ether pentahydrate ; soluble in alcohol, ether
Magnetic susceptibility (χ)	−93.0·10−6 cm3/mol
Structure
Molecular shape	Square planar
Hazards
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	276 mg/kg (rat, oral)
Related compounds
Other anions	Platinum(IV) bromide ; Platinum(IV) fluoride ; Platinum(IV) sulfide
Other cations	Iridium(IV) chloride
Related compounds	Platinum(II) chloride ; Platinum(VI) fluoride
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Platinum(IV) chloride is the inorganic compound of platinum and chlorine with the empirical formula PtCl₄. This brown solid features platinum in the 4+ oxidation state.

Structure

Typical of Pt(IV), the metal centers adopt an octahedral coordination geometry, {PtCl₆}. This geometry is achieved by forming a polymer wherein half of the chloride ligands bridge between the platinum centers. Because of its polymeric structure, PtCl₄ dissolves only upon breaking the chloride bridging ligands. Thus, addition of HCl give H₂PtCl₆. Lewis base adducts of Pt(IV) of the type cis-PtCl₄L₂ are known, but most are prepared by oxidation of the Pt(II) derivatives.


Part of a (PtCl₄)_∞ chain from the crystal structure of platinum(IV) chloride

Formation and reactions

PtCl₄ is mainly encountered in the handling of chloroplatinic acid, obtained by dissolving of Pt metal in aqua regia. Heating H₂PtCl₆ gives PtCl₄:

H₂PtCl₆ → PtCl₄ + 2 HCl

If excess acids are removed, PtCl₄ crystallizes from aqueous solutions in large red crystals of pentahydrate PtCl₄·5(H₂O),^[1] which can be dehydrated by heating to about 300 °C in a current of dry chlorine. The pentahydrate is stable and is used as the commercial form of PtCl₄.

Treatment of PtCl₄ with aqueous base gives the [Pt(OH)₆]²⁻ ion. With methyl Grignard reagents followed by partial hydrolysis, PtCl₄ converts to the cuboidal cluster [Pt(CH₃)₃(OH)]₄.^[2] Upon heating PtCl₄ evolves chlorine to give PtCl₂:

PtCl₄ → PtCl₂ + Cl₂

The heavier halides, PtBr₄ and PtI₄, are also known.

References

Cotton, S. A. Chemistry of Precious Metals, Chapman and Hall (London): 1997. ISBN 0-7514-0413-6.

^ George Samuel Newth (1920). A text-book of inorganic chemistry. Longmans, Green, and co. p. 694.
^ Greenwood, N. N.; & Earnshaw, A. (1997). Chemistry of the Elements (2nd Edn.), Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4.

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[1] George Samuel Newth (1920). A text-book of inorganic chemistry. Longmans, Green, and co. p. 694.

[2] Greenwood, N. N.; & Earnshaw, A. (1997). Chemistry of the Elements (2nd Edn.), Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4.

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