Platinum(IV) chloride

Platinum(IV) chloride
Names
	IUPAC name Platinum tetrachloride
	Other names 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
EC Number	236-645-1;
PubChem CID	26031;
RTECS number	TP2275500;
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)
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
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H290, H301, H314, H317, H334
Precautionary statements	P234, P260, P261, P264, P270, P272, P280, P285, P301+P310, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P304+P341, P305+P351+P338, P310, P321, P330, P333+P313, P342+P311, P363, P390, P404, P405, P501
	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.^[2]


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 to 220 °C gives impure PtCl₄:^[3]

H₂PtCl₆ → PtCl₄ + 2 HCl

A purer product can be produced by heating under chlorine gas at 250 °C.^[4]

If excess acids are removed, PtCl₄ crystallizes from aqueous solutions in large red crystals of pentahydrate PtCl₄·5(H₂O),^[5] 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.^[6] 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.

^ "Platinum tetrachloride". pubchem.ncbi.nlm.nih.gov. Retrieved 27 December 2021.
^ M. F. Pilbrow (1972). "Crystal structure of platinum tetrachloride". Journal of the Chemical Society, Chemical Communications (5): 270–271. doi:10.1039/C39720000270.
^ A. E. Schweizer; G. T. Kerr (1978). "Thermal decomposition of hexachloroplatinic acid". Inorganic Chemistry. 17 (8): 2326–2327. doi:10.1021/ic50186a067.
^ Handbuch der präparativen anorganischen Chemie. 1 (3., umgearb. Aufl ed.). Stuttgart: Enke. 1975. p. 1709. ISBN 978-3-432-02328-1.
^ 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.

[1] "Platinum tetrachloride". pubchem.ncbi.nlm.nih.gov. Retrieved 27 December 2021.

[crys-2] M. F. Pilbrow (1972). "Crystal structure of platinum tetrachloride". Journal of the Chemical Society, Chemical Communications (5): 270–271. doi:10.1039/C39720000270.

[decomp-3] A. E. Schweizer; G. T. Kerr (1978). "Thermal decomposition of hexachloroplatinic acid". Inorganic Chemistry. 17 (8): 2326–2327. doi:10.1021/ic50186a067.

[brauer-4] Handbuch der präparativen anorganischen Chemie. 1 (3., umgearb. Aufl ed.). Stuttgart: Enke. 1975. p. 1709. ISBN 978-3-432-02328-1.

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

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

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