White monoclinic crystal or crystalline powder. Odorless. It is hygroscopic. One molecule of crystal water was lost at 128 ° C, and all of the water was lost at 163 ° C. Soluble in acid, sodium thiosulfate and ammonium salt solution, soluble in 400 parts of water, less soluble in hot water, very slowly soluble in glycerin, almost insoluble in ethanol and most organic solvents. The relative density is 2.32. Irritating. It usually contains 2 crystal waters, which exist in the form of gypsum ore in nature.

Basic Information

Calcium sulfate

Chemical formula: CaSO4

CAS registration number: 10101-41-4

Appearance: white powder

Melting point: 1450 °C

Molecular weight: 136

Aliase: anhydrite

Density: 2.96

Calcium sulfate (CaSO4) is a colorless orthogonal or monoclinic crystal, and the monoclinic crystal has a melting point of 1450 ° C and a 1193 ° C orthogonal to monoclinic crystal. The density is 2.61 g/cm 3 and is slightly soluble in water. Can be decomposed above 1200 °C:

2CaSO4 ==1200°C== 2CaO+2SO2↑+O2↑