/thuy'oh yoo ree"euh, -yoor"ee euh/, n. Chem.a colorless, crystalline, bitter-tasting, water-soluble solid, CH4N2S, derived from urea by replacement of the oxygen with sulfur: used chiefly in photography, inorganic synthesis, and to accelerate the vulcanization of rubber. Also called thiocarbamide.[1890-95; < NL; see THIO-, UREA]
* * *also called thiocarbamidean organic compound that resembles urea (q.v.) but contains sulfur instead of oxygen; i.e., the molecular formula is CS(NH2)2, while that of urea is CO(NH2)2. Like urea, it can be prepared by causing a compound with the same chemical composition to undergo rearrangement, as by heating ammonium thiocyanate (NH4SCN). A method of preparation more commonly used consists of the addition of hydrogen sulfide to cyanamide. Thiourea exhibits many of the chemical properties of urea, but it has little commercial application. The small quantity of thiourea consumed is utilized primarily in photography as a fixing agent, in the manufacture of a thermosetting resin, as an insecticide, as a textile-treating agent, and as starting material for certain dyes and drugs. Thiourea forms as colourless crystals melting at 182° C (360° F). It is toxic, although the fatal dosage is not well established.
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