Platinum(IV) chloride is the

inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...

platinum Platinum is a chemical element with the symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Its name originates from Spanish , a diminutive of "silver". Platinu ...

and

chlorine Chlorine is a chemical element with the Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate betwee ...

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 In chemistry, octahedral molecular geometry, also called square bipyramidal, describes the shape of compounds with six atoms or groups of atoms or ligands symmetrically arranged around a central atom, defining the vertices of an octahedron. The oc ...

, . 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 ligand In coordination chemistry, a bridging ligand is a ligand that connects two or more atoms, usually metal ions. The ligand may be atomic or polyatomic. Virtually all complex organic compounds can serve as bridging ligands, so the term is usually r ...

s. Thus, addition of HCl give H₂PtCl₆.

Lewis base A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any sp ...

adduct An adduct (from the Latin ''adductus'', "drawn toward" alternatively, a contraction of "addition product") is a product of a direct addition of two or more distinct molecules, resulting in a single reaction product containing all atoms of all co ...

s of Pt(IV) of the type cis-PtCl₄L₂ are known, but most are prepared by oxidation of the Pt(II) derivatives.

Formation and reactions

PtCl₄ is mainly encountered in the handling of

chloroplatinic acid Chloroplatinic acid (also known as hexachloroplatinic acid) is an inorganic compound with the formula 3Osub>2 tCl6H2O)''x'' (0 ≤ ''x'' ≤ 6). A red solid, it is an important commercial source of platinum, usually as an aqueous solution. Alth ...

, 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), 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 t(OH)₆sup>2− ion. With methyl

Grignard reagent A Grignard reagent or Grignard compound is a chemical compound with the general formula , where X is a halogen and R is an organic group, normally an alkyl or aryl. Two typical examples are methylmagnesium chloride and phenylmagnesium bromide ...

s followed by partial hydrolysis, PtCl₄ converts to the cuboidal cluster t(CH₃)₃(OH)sub>4.Greenwood, N. N.; & Earnshaw, A. (1997). ''Chemistry of the Elements'' (2nd Edn.), Oxford:Butterworth-Heinemann. . Upon heating PtCl₄ evolves

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. . Chlorides Chlorides,4 Platinum group halides {{inorganic-compound-stub