According to the data of Bao Zheng Medical Education Network, when gypsum is burned in a bottle with a soft hole and a small cork, dehydration reaction will occur, that is, the crystallized water in gypsum will be evaporated to form anhydrous gypsum. This is because gypsum molecules contain crystal water. When heated, water molecules volatilize due to the increase in temperature. After gypsum molecules lose water, the intermolecular structure changes, forming a new chemical substance-anhydrous gypsum.

Anhydrous gypsum is a white or gray powder, which is more stable and more widely used than gypsum. Anhydrous gypsum is often used in architecture, ceramics, cosmetics and so on. In addition, anhydrous gypsum can also promote plant growth, so it is also used in agriculture.