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.
Many compounds are found in crystal form with water attached. These compounds are called hydrates and the crystals with water attached are called hydrated crystals.The formula for the hydrated crystal tells how many water molecules are attached to each formula unit of crystal.For example, hydrated calcium nitrate is written: Ca(NO3)2 (4 H2O and is called calcium nitrate tetrahydrate.he formula for the hydrated crystal tells how many water molecules are attached to each formula unit of crystal. For example, hydrated calcium nitrate is written: Ca(NO3)2 (4 H2O and is called calcium nitrate tetrahydrate.