HYDRATE

n. Hid'rat. Lat., hydras, hydratum (from vSiap, water). Fr., h. Ger., Hijdrat. It., idrato. Sp., hidrato. 1. Originally, a compound of an element or radicle with water. The term is still used in this sense in speaking of crystalline substances in which water (water of crystallization) forms a part of the chemical or physical organization. Thus ordinary sulphate of copper, CuSO4,5HaO, is spoken of as a h. of the dried or anhydrous sulphate, CuSO4. 2. In the usual sense of the term, a compound of a metal or radicle with hydroxyl (OH). Such compounds may be regarded as water in which an atom of hydrogen is replaced by an atom or molecule of the combining radicle. Such compounds are now often denominated hydroxides, to avoid confusion with h. in the first sense. [B.] Haloid h. Ger., Haloidhydrat. A h., or compound of a radicle with two or more molecules of hydroxyl, in which one of the molecules of hydroxyl is replaced by a haloid element. [B.] H. alumin i que (Fr.). See TERRA argil lace a para. [s. 377]