Bismuth Thiocyanate, Bi(CNS)3, is obtained when thiocyanic acid is neutralised with bismuth hydroxide. It is possible that a basic compound is also obtained. Dilute thiocyanic acid solution must be used; basic substances are probably formed first, but on cooling, bright orange or amber-coloured rhombic crystals of normal bismuth thiocyanate separate, having the elements
a:b:c = 0.76134:1:0.28423
The crystals are decomposed by water, and on heating. The hydrate Bi(CNS)3.14H2O is obtained in the form of deep-red transparent needles by the action of excess of thiocyanic acid upon bismuth carbonate; when the acid is saturated with bismuth carbonate, basic bismuth thiocyanate, Bi(CNS)2OH.5H2O, separates in glistening plates on addition of alcohol. |