(also rhodanic acid), HSCN, a colorless, oily liquid with a pungent odor and a melting point of 5°C. Thi-ocyanic acid is stable only at low temperatures (approximately -90°C) or in dilute aqueous solutions (less than 5 percent), where it is almost completely dissociated. Only the derivatives of thiocyanic acid, for example, the thiocyanates, and the esters are of practical importance; the latter are used as insecticides and fungicides.