Ferrous bromborate, FeBr₂.6FeO.8B₂O₃

Ferrous bromborate, FeBr₂.6FeO.8B₂O₃ or FeBr₂.6FeB₂O₄.2B₂O₃, is prepared by passing bromine vapour over an intimate mixture of iron (in excess) and boro-natro-calcite, Na₂B₄O₇.Ca₂B₆O₁₁.16H₂O. It yields greyish white cubes and octahedra.