For example, when a solution of a ferric salt is added to a solution of potassium thiocyanate, a deep red coloration is produced, owing to the formation of ferric thiocyanate.
Chromic thiocyanate, Cr(SCN) 3, an amorphous deliquescent mass, is formed by dissolving the hydroxide in thiocyanic acid and drying over sulphuric acid.
The double thiocyanate, Cr(SCN) 3.3KCNS 4H 2 O, is also known.
When heated for some time with water to 140° C. in a sealed tube, it is transformed into ammonium thiocyanate, a similar result being obtained by heating the base alone for some hours to 160-170° C. On heating alone for some hours to r70-180° C. it is converted into guanidine thiocyanate.
Thiosemicarbazide, NH 2 CS NH NH 2, prepared from hydrazine sulphate, potassium carbonate and thiocyanate (N.
Ferrous salts also give a bluish white precipitate with ferrocyanide, which on exposure turns to a dark blue; ferric salts are characterized by the intense purple coloration with a thiocyanate.
Ferric thiocyanate has been suggested, and sulphur is said to have been detected in the mineral.