The French use the word chateau for castle but it used to cover both: the Chateau-Gaillard, a fortress of the 12th century; and the manors dating from the 12th to the 18th century, which have no or little defensive capability.he French use the word chateau for castle but it used to cover both: the Chateau-Gaillard, a fortress of the 12th century; and the manors dating from the 12th to the 18th century, which have no or little defensive capability.
Hydrate, any compound containing water in the form of H2O molecules, usually, but not always, with a definite content of water by weight. The best-known hydrates are crystalline solids that lose their fundamental structures upon removal of the bound water.
Some ionic compounds incorporate water molecules in their structure. These compounds are called hydrates. To name the hydrates, the number of waters of hydration is indicated by a Greek prefix following the name of the compound. For example, CuSO 4 5H 2 O is called copper(II) sulfate pentahydrate.