dihydrate

例句：

1. 1. The dihydrate of sodium chloride is used as a preservative in food packaging.
   氯化钠的二水合物用作食品包装中的防腐剂。
2. 2.The hydrates are important for the growth of many plants.
   这些化合物对许多植物的生长至关重要。
3. 3. The dihydrate forms when water is added to the solution of the salt.
   当向盐溶液中加入水时，二水合物会形成。