Brome Bleaching Powder

Berzelius first observed that bromine reacts with calcium hydroxide forming a reddish compound with bleaching properties. Killby has stated that brome bleaching powder contains bromine in three forms: as bromide, hypobromite, and finally, in a more loosely combined form, probably as the perbromide, thus giving the red colour. Wilks regarded the reaction as an adsorption of the bromine by the lime, rather than chemical combination as between chlorine and lime.

By heating the red compound at 100° C. until no more water and bromine are driven off, there is formed a pale yellow powder containing 33 per cent, of available bromine and having substantially the composition CaO.CaBrOBr.H₂O, which recalls Ditz's intermediate compound (see under Bleaching Powder). This yellow product has bactericidal and bleaching properties.