Selenocyanic Acid, HCNSe

Selenocyanic Acid, HCNSe, may be prepared in solution by decomposing the lead salt (obtained by treating potassium selenocyanate with lead acetate) with hydrogen sulphide. It is stable only in neutral or alkaline solution. Selenocyanuric acid has been obtained as a red amorphous powder by the action of cyanuric chloride on sodium selenide and subsequent precipitation by acids.