Ferric chloro-bromide, FeCl₂Br

Ferric chloro-bromide, FeCl₂Br, is obtained as an unstable crystalline substance by heating ferrous chloride and excess bromine in sealed tubes at 100° C. The crystals are dark coloured and lustrous, appearing green by reflected light and quite opaque, even in thin sections. Although insoluble in bromine, they readily dissolve in water, ether, or alcohol, their solubility in ether rendering easy their separation from ferrous chloride. The crystals readily decompose on warming, but sublime unchanged if heated in a tube containing a slight excess of bromine.