Thorium Oxybromide, ThOBr₂

Thorium Oxybromide, ThOBr₂, is formed when an aqueous solution of the tetrabromide is evaporated to dryness and the residue is heated to 160° C. (Moissan and Martinsen); it is also obtained as a white, amorphous, friable mass by the method of Bourion (see above), and dissolves completely in water with slight hissing. From a solution of thorium hydroxide in alcoholic hydrogen bromide the crystalline hydroxybromides Th(OH)₂Br₂.4H₂O and Th(OH)Br₃.10H₂O have been obtained.