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Platinum(IV) chloride

Platinum(IV) chloride
Platinum(IV) chloride
Names
IUPAC name
Platinum tetrachloride
Other names
Platinum(IV) chloride
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.033.300 Edit this at Wikidata
EC Number
  • 236-645-1
RTECS number
  • TP2275500
UNII
  • InChI=1/4ClH.2Pt/h4*1H;;/q;;;;2*+2/p-4
    Key: KBPRWZWTZAMEIF-XBHQNQODAX
  • 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
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)
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
−93.0·10−6 cm3/mol
Structure
Square planar
Hazards
GHS labelling:[1]
GHS05: CorrosiveGHS06: ToxicGHS07: Exclamation markGHS08: Health hazard
Danger
H290, H301, H314, H317, H334
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):
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).

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.
  1. ^ "Platinum tetrachloride". pubchem.ncbi.nlm.nih.gov. Retrieved 27 December 2021.
  2. ^ M. F. Pilbrow (1972). "Crystal structure of platinum tetrachloride". Journal of the Chemical Society, Chemical Communications (5): 270–271. doi:10.1039/C39720000270.
  3. ^ A. E. Schweizer; G. T. Kerr (1978). "Thermal decomposition of hexachloroplatinic acid". Inorganic Chemistry. 17 (8): 2326–2327. doi:10.1021/ic50186a067.
  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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