Potassium platinocyanide

K[(CH3)3Pt]Pt(CN)4, is isolated from an aqueous solution of the nitrate by adding potassium platinocyanide. A slimy yellow precipitate is formed, insoluble in water and the usual organic solvents except acetone and alcohol. On evaporation from one of these solvents an amorphous resinous greenish-yellow compound is produced which, from determination of the platinum, appears to correspond to K2Pt(CN)4[(CH3)3Pt]2Pt(CN)4. 

By precipitation of the metallic platinocyanide, when insoluble in water, by double decomposition of a soluble salt of the metal with potassium platinocyanide solution. In this manner Martius obtained the copper salt ... 

Oxidation.—In early literature 2 it is stated that by the action of chlorine, bromine, iodine, lead peroxide or nitric acid upon potassium platinocyanide, a new product, potassium platinicyanide, K2Pt(CNJs. 3H20, is obtained. Similar statements may be found in some recent text-books, but are nevertheless quite incorrect. 

When potassium platinocyanide in aqueous solution is acted upon by chlorine or bromine, a halogenated product of composition corresponding to the formula 3 (in the case of bromine)... 

Oxidation of potassium platinocyanide with lead peroxide, acidulated with dilute sulphuric acid, yields a product containing the S04 group,1 of formula3 a K2Pt(CN)4.K2Pt(CN)4.S04, where x is probably 9 but again no platinicyanide is formed. 

If, however, a solution of potassium platinocyanide is treated with hydrogen peroxide (20-volume solution) acidulated with dilute sulphuric acid, potassium platinicyanide, KPt(CN)4, is obtained, united with three molecules of platinocyanide, thus 8K2Pt(CN)4.KPt(CN)4.6H20. Lithium platinocyanide is more readily oxidised in this manner, yielding 2Li2Pt(CN) 4. LiPt(CN)1 and if the hydrogen peroxide is replaced by Merck s pure perhydrol, complete oxidation to lithium platinicyanide, LiPt(CN)4, is obtained. 

Calcium Ammonium and Calcium Potassium Platinocyanides have also been obtained.3... 

Lead Platinocyanide, PbPt(CN)4, is readily prepared by mixing boiling saturated solutions of potassium platinocyanide and lead acetate. The solution remains clear, but on cooling the lead salt separates out as a yellowish white crystalline powder.4 It is anhydrous, and becomes yellow on warming in air, then white whilst at higher temperatures cyanogen is liberated, the residue containing metallic lead and platinum. 

Wilm 8 drew attention to the fact that the properties of potassium platinocyanide vary somewhat according to the method of preparation. When white, fluorescent crystals of the salt are boiled with hydrogen... 

Sodium Potassium Platinocyanide, NaKPt(CN)4.3H20, results when the copper salt is decomposed with a mixed solution of sodium and potassium carbonates.4 It crystallises in beautiful orange-coloured monoclinic prisms, and closely resembles the barium potassium salt. Its crystallographic elements are 3 ... 

At 160° C. the salt becomes white and anhydrous. By crystallising mixed solutions of strontium and potassium platinocyanides the double salt Strontium Potassium Platinocyanide, SrK2[Pt(CN)4]2,4H20, is obtained. 

Zinc Platinocyanide, ZnPt(CN)4, is obtained as an insoluble yellowish white product on treating potassium platinocyanide solution with... 

If the (much dearer) chemical, barium platinocyanide be used, tne phosphorescence is much stronger and of a greenish tinge. It is with this chemical that X Ray screens are coated. Another chemical almost equally brilliant (phosphorescing blue) is potassium platinocyanide it is also equally dear. 

According to some authorities, the first metal ammine to be isolated in the solid state was the reddish yellow hexaamminecobalt(III) oxalate [Co(NH3)6]2(C204)3, described in 1822 by Leopold Gmelin (1788-1853).16 Gmelin also discovered several new double salts potassium ferricyanide, or potassium hexacyanoferrate(III), K3[Fe(CN)6l>17 the cobalticyanides or hexacyanocobaltates(III), M3[Co(CN) ],18 and the platinocyanides or tetracyanoplatinates(II), M2[Pt(CN)4].19All these substances certainly deserve to rank among the earliest known coordination compounds. 

A soluble form of platinous cyanide is obtained as a yellow precipitate by decomposing a solution of a platinocyanide with sulphuric acid. It dissolves easily in alkalies and in potassium cyanide solution, but is usually contaminated with small quantities of sulphate. 

By warming platinum salt solutions with alkali or alkaline earth cyanides and allowing to crystallise. In this manner the potassium salt, the first platinocyanide to be obtained, namely, by Ittner, was prepared ... 

Potassium Barium Platinocyanide, BaK2[Pt(CN)4]2.Aq, is obtained by crystallising mixed solutions of barium and potassium platino-cyanides. In appearance it resembles the sodium potassium salt.3... 

Potassium Lithium Platinocyanide, KLiPt(CN)4.3H20, has also been prepared4 as yellowish green crystals. 

Sodium Platinocyanide, Na2Pt(CN)4.3H20, was first prepared by Quadrat,1 who decomposed the copper salt with sodium hydroxide. It also results on decomposing the barium salt with sodium sulphate.2 Martius acted on the potassium salt in concentrated solution with hydrofluosilicie acid, and saturated the filtrate with sodium carbonate. 

Platinum blue is mentioned in the 1869 Salter edition of Field s Chromatography. He states that With mercurous nitrate, the platinocyanide of potassium forms a thick smalt blue, and the pla-tinidcyanide a dark blue precipitate. The compound is a mixture of platino- or platinidcyanide of mercury and mercurous nitrate. ... 

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