Cerous chloride, CeCl₃

Bourion's sulphur chloride method, starting with ceric oxide, is very convenient. The Cerous chloride, CeCl₃, is a white, crystalline, hygroscopic solid, readily soluble in water.

Anhydrous cerous chloride readily absorbs ammonia. The following compounds have been prepared, and their dissociation pressures measured: CeCl₃.2ONH₃, CeCl₃.8NH₃, CeCl₃.2NH₃, CeCl₃.12NH₃, CeCl₃.4NH₃.

An aqueous solution of cerous chloride may be prepared by heating ceric hydroxide with concentrated hydrochloric acid, chlorine being evolved. On saturating the cold solution with hydrogen chloride, orthorhombic crystals (a:b:c = 0.8083:1:1.4419) of the heptahydrate, CeCl₃.7H₂O, separate. A triclinic salt (a:b:c = 1.1580:1:08635; α = 91°3', β = 114°9', γ = 88°12') has also been described, isomorphous with lanthanum chloride heptahydrate, but it is said to be the. hexahydrate, CeCl₃.6H₂O.

The following double salts are known, in addition to those containing metals of Groups IV. and V. and organic bases: - CeCl₃.4HgCl₂.10H₂O; CeCl₃.3Hg(CN)₂.8H₂O; CeCl₃.AuCl₃.13H₂O; CeCl₃.2PtCl₂.10H₂O; CeCl₃.2PtCl₄.12H₂O.