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.
Molar Weight | 172.17 g/mol (dihydrate) |
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Melting Point | 1,460°C (anhydrous) |
Flash Point | non flammable |
Density | 2.32 g/cm³ (dihydrate) |
Forms | Powder, White, Solid |
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)