Molybdenum Dibromide, MoBr₂

Molybdenum Dibromide, MoBr₂, is obtained by heating the tribromide, or by strongly heating the metal in bromine vapour. It is a reddish-yellow substance, stable in air, insoluble in water and in acids; in dilute alkalies it is soluble with formation of a hydrate, but by concentrated alkalies it is decomposed. For reasons similar to those applying in the case of the chloride, the formula of the bromide is considered to be (Mo₃Br₄)Br₂.

Molybdenum dibromide forms a hydroxy-compound Mo₃Br₄(OH)₂, of which the octa- and di-hydrates have also been obtained. In addition, a fluorobromide, Mo₃Br₄F₂.3H₂O, and chlorobromides of molybdenum, Mo₃Cl₄Br₂.3H₂O, Mo₃Cl₄Br₂.6H₂O, and Mo₃Cl₂Br₄.3H₂O, and the kydroxychlorobromide, Mo₃Cl₄Br.OH.2H₂O, have been prepared.