Platinum(IV) chloride
{{chembox
| ImageFile = Platinum(IV) chloride.jpg
| ImageSize =
| ImageFile1 = Platinum(IV)-chloride-2D.png
| ImageSize1 = 250px
| ImageName1 = Platinum(IV) chloride
| IUPACName = Platinum tetrachloride
| OtherNames =Platinum(IV) chloride
|Section1={{Chembox Identifiers
| CASNo = 13454-96-1
| CASNo_Ref = {{cascite|correct|CAS}}
| ChemSpiderID = 19957150
| EC_number = 236-645-1
| PubChem = 26031
| RTECS = TP2275500
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = W3YUG71TU2
| InChI = 1/4ClH.2Pt/h4*1H;;/q;;;;2*+2/p-4
| SMILES = [Pt+4].[Cl-].[Cl-].[Cl-].[Cl-]
| SMILES_Comment = ionic monomer
| SMILES1 = Cl[Pt](Cl)(Cl)Cl
| SMILES1_Comment = coordination monomer
| SMILES2 = 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
| SMILES2_Comment = coordination polymer
| InChIKey = KBPRWZWTZAMEIF-XBHQNQODAX
}}
|Section2={{Chembox Properties
| Formula = PtCl4
| MolarMass = 336.89 g/mol
| Appearance = brown-red powder
| Density = 4.303 g/cm3 (anhydrous)
2.43 g/cm3 (pentahydrate)
| Solubility = 58.7 g/100 mL (anhydrous)
very soluble (pentahydrate)
| SolubleOther = anhydrous
soluble in acetone
slightly soluble in ethanol
insoluble in ether
pentahydrate
soluble in alcohol, ether
| MeltingPtC = 370
| MeltingPt_notes = (decomposes)
| BoilingPt =
| MagSus = −93.0·10−6 cm3/mol
}}
|Section6={{Chembox Structure
| MolShape = Square planar
}}
|Section7={{Chembox Hazards
| GHSPictograms = {{GHS05}}{{GHS06}}{{GHS07}}{{GHS08}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|290|301|314|317|334}}
| PPhrases = {{P-phrases|234|260|261|264|270|272|280|285|301+310|301+330+331|302+352|303+361+353|304+340|304+341|305+351+338|310|321|330|333+313|342+311|363|390|404|405|501}}
| LD50 = 276 mg/kg (rat, oral)
}}
|Section8={{Chembox Related
| OtherAnions = Platinum(IV) bromide
Platinum(IV) fluoride
Platinum(IV) sulfide
| OtherCations = Iridium(IV) chloride
| OtherCompounds = Platinum(II) chloride
Platinum(VI) fluoride
}}
}}
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.{{cite journal |author1=M. F. Pilbrow |title=Crystal structure of platinum tetrachloride |journal=Journal of the Chemical Society, Chemical Communications |date=1972 |issue=5 |pages=270-271 |doi=10.1039/C39720000270 |language=en}}
| class="wikitable" style="text-align:center;"
| 400px |
| 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:{{cite journal |author1=A. E. Schweizer |author2=G. T. Kerr |title=Thermal decomposition of hexachloroplatinic acid |journal=Inorganic Chemistry |date=1978 |volume=17 |issue=8 |pages=2326–2327 |doi=10.1021/ic50186a067 |language=en}}
:H2PtCl6 → PtCl4 + 2 HCl
A purer product can be produced by heating under chlorine gas at 250 °C.{{Cite book |title=Handbuch der präparativen anorganischen Chemie. 1 |date=1975 |publisher=Enke |isbn=978-3-432-02328-1 |edition=3., umgearb. Aufl |location=Stuttgart |page=1709}}
If excess acids are removed, PtCl4 crystallizes from aqueous solutions in large red crystals of pentahydrate PtCl4·5(H2O),{{cite book |title=A text-book of inorganic chemistry |author=George Samuel Newth|publisher=Longmans, Green, and co|year=1920|url=https://books.google.com/books?id=n6A9AAAAIAAJ|page=694}} 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.Greenwood, N. N.; & Earnshaw, A. (1997). Chemistry of the Elements (2nd Edn.), Oxford:Butterworth-Heinemann. {{ISBN|0-7506-3365-4}}. Upon heating PtCl4 evolves chlorine to give PtCl2:
:PtCl4 → PtCl2 + Cl2
References
- Cotton, S. A. Chemistry of Precious Metals, Chapman and Hall (London): 1997. {{ISBN|0-7514-0413-6}}.
{{Reflist}}
{{Platinum compounds}}
{{Chlorides}}