Mercuric Selenocyanate, Hg(CNSe)₂

Mercuric Selenocyanate, Hg(CNSe)₂, forms a crystalline mass when mercuric acetate is treated with potassium selenocyanate. The crystalline mass consists of white needles which are slightly soluble in cold water but readily soluble in alkali cyanide, thiocyanate and selenocyanate solutions. Mercuric selenocyanate turns brown in air and is decomposed by heat.

A double compound Hg(CNSe)₂.HgCl₂ has been obtained and described by Crookes. It consists of yellow crystals which are slightly soluble in cold water, more readily soluble in hot water. It is also very soluble in alcohol and in dilute hydrochloric acid, but it appears to decompose in the latter solvent, as the solution deposits selenium after standing for some time.