Silver Selenocyanate, AgCNSe

Silver Selenocyanate, AgCNSe, is obtained as a white precipitate closely resembling silver chloride by the action of silver nitrate on a solution of potassium selenocyanate. If, however, ammonia is previously added in excess to the silver nitrate solution, the selenocyanate is precipitated in minute satin-like crystals.

Silver selenocyanate is readily blackened by the action of light. It is insoluble in water and only very sparingly soluble in ammonia and cold dilute acids. It is decomposed by boiling concentrated acids with the deposition of selenium, unless the acid used has oxidising properties.