Complex Halogen-halides

Two salts, dichlortetraquochromic bromide [(H₂O)₄CrCl₂]Br and dibromtetraquochromic chloride [(H₂O)₄CrBr₂]Cl.2H₂O, have been described, as also has the compound, Cr₂F₂Cl₄.

There is some reason for the belief that the interaction of chromic acid and acetyl bromide causes intermediate formation of unstable chromyl bromide, CrO₂Br₂.