Nitrogen tribromide

Names
IUPAC name nitrogen tribromide
Identifiers
CAS Number	15162-90-0
3D model (JSmol)	Interactive image
ChemSpider	20480821
PubChem CID	3082084
CompTox Dashboard (EPA)	DTXSID90164822
InChI InChI=1S/3BrH.N/h3*1H;/p-3
SMILES N(Br)(Br)Br
Properties
Chemical formula	NBr3
Molar mass	253.7187 g/mol
Appearance	Deep red solid
Melting point	Explodes at -100 °C[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Infobox references

Nitrogen tribromide is a chemical compound with the formula NBr₃. It is extremely explosive in its pure form, even at −100 °C, and was not isolated until 1975.^[2] It is a deep-red and volatile solid.

Preparation

NBr₃ was first prepared by reaction of bistrimethylsilylbromamine (bis(trimethylsilyl)amine bromide) with bromine monochloride (with trimethylsilyl chloride as byproduct) at −87 °C according to the following equation:

(Me₃Si)₂NBr + 2 BrCl → NBr₃ + 2 Me
₃SiCl

where "Me" is a methyl group.

NBr₃ can be produced by the reaction of bromine or hypobromite and ammonia in a dilute aqueous buffer solution.^[3] It can also be prepared by the reaction of bromine and bromine azide.^[4] Ammonia and bromine undergo glow discharge, and after treatment, red NBr₃·6NH₃ can be obtained.^[5] Pure nitrogen NBr₃ was only produced in 1975.^[6]

Reactions

Nitrogen tribromide reacts instantly with ammonia in dichloromethane solution at −87 °C to yield NBrH₂.^[7]

NBr₃ + 2 NH₃ → 3 NH₂Br

It also reacts with iodine in dichloromethane solution at −87 °C to produce NBr₂I, which is a red-brown solid that stable up to -20 °C.^[7]

NBr₃ + I₂ → NBr₂I + IBr

References