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Nitrogen tribromide

Nitrogen tribromide is a chemical compound with the formula NBr<sub>3</sub>. It is extremely explosive in its pure form, even at −100&nbsp;°C, and was not isolated until 1975. It is a deep-red and volatile solid.

Preparation

NBr<sub>3</sub> was first prepared by reaction of bistrimethylsilylbromamine (bis(trimethylsilyl)amine bromide) with bromine monochloride (with trimethylsilyl chloride as byproduct) at −87&nbsp;°C according to the following equation:

(Me<sub>3</sub>Si)<sub>2</sub>NBr + 2 BrCl → NBr<sub>3</sub> + 2

where "Me" is a methyl group.

NBr<sub>3</sub> can be produced by the reaction of bromine or hypobromite and ammonia in a dilute aqueous buffer solution. It can also be prepared by the reaction of bromine and bromine azide. Ammonia and bromine undergo glow discharge, and after treatment, red NBr<sub>3</sub>·6NH<sub>3</sub> can be obtained. Pure nitrogen NBr<sub>3</sub> was only produced in 1975.

Reactions

Nitrogen tribromide reacts instantly with ammonia in dichloromethane solution at −87&nbsp;°C to yield NBrH<sub>2</sub>.

NBr<sub>3</sub> + 2 NH<sub>3</sub> → 3 NH<sub>2</sub>Br

It also reacts with iodine in dichloromethane solution at −87&nbsp;°C to produce NBr<sub>2</sub>I, which is a red-brown solid that stable up to -20&nbsp;°C.

NBr<sub>3</sub> + I<sub>2</sub> → NBr<sub>2</sub>I + IBr

References