Sodium Platinocyanide, Na₂Pt(CN)₄

Sodium Platinocyanide, Na₂Pt(CN)₄.3H₂O, was first prepared by Quadrat, who decomposed the copper salt with sodium hydroxide. It also results on decomposing the barium salt with sodium sulphate. Martius acted on the potassium salt in concentrated solution with hydrofiuosilicic acid, and saturated the filtrate with sodium carbonate.

On concentration the salt separates out as long triclinic prisms closely resembling in properties the potassium salt. The crystallographic elements are:

a:b:c = 0.5879:1: 0.4757; α = 87° 42', β = 94° 56.75', γ = 90° 59.5'.

The salt is soluble both in water and in alcohol. It loses its combined water at about 120° C.