HexaChloroplatinate , ammonium sodium

Compounds Ammonium chloroplatinate sodium chloroplatinate platinic chloride platinum chloride sodium tetrachloroplatinate potassium tetrachloroplatinate ammonium tetrachloroplatinate sodium hexachloroplati-nate potassium hexachloroplatinate ammonium hexachloroplatinate... 

None of the accepted preparative methods12 for disodium hexa-chloroplatinate(IV), Na2[PtCl6], is entirely suitable for routine use, because these procedures require reaction of a mixture of solid sodium chloride and platinum metal with chlorine gas at temperatures near 500°. However, a preparation of the desired compound is described below which yields a product of very high purity and which is much more convenient than those previously reported since only solution chemistry is involved. Unlike the corresponding ammonium and potassium salts, disodium hexachloroplatinate(IV) exhibits high solubility in water and in several nonaqueous solvents, including ethanol, methanol, and Ar,/V-dimethylformamide—a fact which enables one to extend the range of studies of the chemistry of hexachloroplatinate(IV). 

The work of Alfred Werner led to a considerable understanding of the stereochemistries of arrangements of ligands. This understanding was reinforced by X-ray diffraction studies of metal complexes, for example, in the determination of the structures of ammonium hexachloroplatinate and chloropalladite, shown in Figure 15.4. In these there are six groups around the metal ion, at an equal distance, rather like a small portion of the sodium chloride structure. 

This, together with [IrCle] " and [IrBre] in ammonium or sodium hexachloroplatinate host lattices, has been well studied 136, 294, 295, 546). The [IrClg] " spectrum (296, 546) is an often-quoted classic since it was the first example of ligand s.h.f.s., proving for the first time that electron delocalization was possible and that the electron spent 30% of its time on the ligands. The g values of the tertiary arsine and phosphine complexes of IrCl4X2 have been measured (358) (see Table XLII). 

History. William Hyde Wollaston discovered palladium in 1803 in crude platinum ore from South America. He dissolved the ore in aqua regia, neutralized the acid with sodium hydroxide (NaOH), and precipitated the platinum by treatment with ammonium chloride, NH Cl, as ammonium hexachloroplatinate (NH PtCl ). Palladium was then removed as palladium cyanide by treatment with mercuric cyanide. The free metal was produced from this cyanide by heating. 

---