The hypobromite ion, also known as alkaline bromine water, is BrO−. Bromine is in the +1 oxidation state. The Br–O bond length is 1.82 Å. [1] Hypobromite is a bromine compound similar to common bleach and hypochlorite found in immune cells. In many ways, hypobromite functions in the same way as hypochlorite, and is also used as a fungicide and antiparasitic in industrial applications and in the immune system.
Hypobromite is formed when bromine is treated with an aqueous base such as sodium or potassium hydroxide. Responses rapidly at 20 °C. [2]
Br2 + 2 OH−(aq) → Br− + BrO− + H2O
In this reaction, bromine disproportionates from oxidation state 0 (Br2) (some undergoing reduction and some oxidation) to oxidation state -1 (Br-) and oxidation state +1 (BrO-). Sodium hypobromite can be isolated as an orange solid.
The secondary reaction, in which hypobromite spontaneously disproportionates to bromide (bromide oxidation state -1) and bromate (bromide oxidation state +5), occurs rapidly at 20 °C and slowly at 0 °C.
3 BrO− → 2 Br− + BrO−
3
Thus, in Reaction 2, the formation and ratio of products in the oxidation states of -1, +1, and +5 bromide can be controlled by temperature. Hypobromite is not thermodynamically stable at any pH (see Pourbaix diagram for bromine.
Hypobromite is a compound that contains this anion. Examples include sodium hypobromite and potassium hypobromite.
