Hydrate

Hydrates are compounds formed by the union of water with some other substance, generally forming a neutral body, as certain crystallized salts.

These substances do not contain water as such, but have their constituents (hydrogen, oxygen, hydroxyl) so arranged that water may be eliminated. Hence, a hydrates are derivatives of, or compounds with, hydroxyl.

Examples include: hydroxide, ethyl hydrate (common alcohol), clathrate hydrate, calcium hydrate, or slaked lime.