Urea: Carbamide; carbonyldianide. H₂NCONH₂; mol. wt. 60.06. CH₄N₂O; C 20.00%, H 6.71%, N 46.65%. Product of protein metabolism. From cyanamide by hydrolyze from CO₂ by ammonolysis: Werner, The Chemistry of Urea (London).

Tetragonal prisms. Develops odor of NH₃. Cooling, saline taste. m. 132.70. On further heating it decomp. to biuret, NH₃, and cyanuric acid. (Ref.) d¹⁸₄ 1.32; d¹⁸₄ of water solns. ( w / w ): 10% 1.027; 20% 1.054; 50% 1.145. pH of a 10% water soln. = 7.2. One gram dissolves in 1 ml. water, 10 ml. 95% alcohol, 1 ml. boiling 95% alcohol, 20 ml. abs. alcohol, 6 nil. methanol, 2 ml. glycerol, almost insoluble in chloroform, ether; soluble in concd. HCl. Water solm. decomp. on heating, giving off some NH₃.

Use: In Hydroculture, fertilizer, because of easily available high nitrogen content. Is reacted with aldehydes to make resins and plastics. Is condensed with malonic ester to form barbituric acid.

Grades available: Reagent, U.S.P., technical.

Med. Use: Diuretic. Has been used in infected wounds and indolent ulcers.

Contraindications: Impaired renal function. Dose: 0.5 to 8 g.

Vet. Use: As for allantoin. Partial source of dietary nitrogen for ruminants.