Calcium Sulphate

Calcium sulphate is an inorganic white solid with the formula CaSO4. It occurs naturally as a mineral and is also produced synthetically, often as a by-product (e.g. from desulphurisation). The compound exists in three levels of hydration: anhydrous (as mineral anhydrite), dihydrate (gypsum or as mineral selenite) and hemihydrate (Bassanite or plaster of Paris).All forms are poorly soluble in water and cause permanent hardness in water.

Synonyms

Gypsum, E516, Plaster of Paris, Anhydrite, Selenite, Alabaster

Chemical Formula

CaSO4

CAS Number

7778-18-9 (anhydrous), 10034-76-1 (hemihydrate), 10101-41-4 (dihydrate)