Crystals or soft, odorless, granules or powder. Slightly bitter, alkaline taste. Readily absorbs CO2 from air forming CaCO3. Loses water when ignited; forms CaO. d 2.08-2.34. Slightly sol in water; sol in glycerol, sugar or NH4Cl solns; sol in acids with evolution of much heat. pH of aq soln satd at 25° 12.4. Keep well closed. LD50 orally in rats: 7.34 g/kg (Smyth).

In mortar, plaster, cement and other building and paving materials; in lubricants, drilling fluids, pesticides, fireproofing coatings, water paints; as egg preservative; manuf of paper pulp; in SBR rubber vulcanization; in water treatment; dehairing hides