Cyanic acid (also called fulminic acid) is an unstable (explosive), poisonous, volatile, clear liquid with the structure of H-O-C=N (the oxoacid formed from the pseudohalogen cyanide), which readily polymerizes to cyamelide and fulminic acid. Cyanuric acid (also called pyrolithic acid), white monoclinic crystal with the structure of [HOC(NCOH)2N], is the compound of polymerized cyanic acid.
Cyanic acid hydrolyses to ammonia and carbon dioxide in water. Its salts and esters are cyanates (or called fulminates). Esters of normal cyanic acid are not known. There is another isomeric cyanic acid with the structure of H-N=C=O, which is called isocyanic acid. Its salts and esters are isocyanates. Cyanates (or Isocyanates) are used in the manufacturing pharmaceuticals, pesticides, textile softener, lubricants and industrial disinfectants through the conversion to polycyclic compounds (such as hydantoins and imidazolons)
They are used as plastic additives and as heat treatment salt formulations for metals. Thiocyanate is a salt or ester of thiocyanic acid (HSCN). Aqueous solutions of thiocyanic acid , also called sulfocyanic acid, are very strong acids of the equilibrium mixture of thiocyanic and isothiocyanic. Thiocyanates are bonded through the sulfur(s) with the structure R-S-C¡ÕN or the isomeric R-N=C=S (isothiocyanates). Thiocyanates are bonded through the sulfur(s) which replace for the oxygen (O) atom. Thiocyanates are the sulfur analog of isocyanates. Organic as well as metallic thiocyanates [CuSCN, Ca(SCN)2, NaSCN, KSCN] are very versatile compounds. They have wide range of applications including manufacturing industrial chemicals, pharmaceuticals and pesticides. It is used in freezing solutions, fabric dyeing, electroplating, steel pickling, printing, and corrosion inhibitor against acid gases. It is used in photography industry as a stabilizer or accelerator.