# Calcium sulfate, CaSO4

Calcium sulfate (CaSO4) is an inorganic compound that exists in various forms including anhydrite (anhydrous) and gypsum (dihydrate). It possesses an orthorhombic crystal structure in its anhydrous form and a monoclinic structure as gypsum. While it has limited direct applications in the field of optics, it serves as a crucial material in industrial processes. It is often used as a filler in the production of paper and textiles and acts as a coagulant in water treatment. Calcium sulfate is also employed in the construction industry as a component of drywall and plasters. Its low solubility in water makes it ideal for soil treatment, where it helps to break down heavy clay soils. In the medical field, gypsum is used for making orthopedic casts. Calcium sulfate is commonly synthesized through the neutralization of sulfuric acid with calcium carbonate or as a byproduct in various industrial processes. Its diverse applications make it an economically significant material across multiple sectors.

## Other names

- Plaster of Paris
- Drierite
- Gypsum

## Mineral

- Anhydrite

## External links

- Calcium sulfate - Wikipedia
- Anhydrite - Wikipedia
- Birefringence - Wikipedia