Dibromine monoxide

Dibromine monoxide is the chemical compound composed of bromine and oxygen with the formula Br₂O. It is a dark brown solid which is stable below −40 °C and is used in bromination reactions.^[1] It is similar to dichlorine monoxide, the monoxide of its halogen neighbor one period higher on the periodic table. The molecule is bent, with C_2v molecular symmetry. The Br−O bond length is 1.85 Å and the Br−O−Br bond angle is 112°,^[2][3] similar to dichlorine monoxide.

Dibromine monoxide

Names
IUPAC name Dibromine monoxide
Systematic IUPAC name Bromo hypobromite
Other names Dibromine oxide, bromine monoxide
Identifiers
CAS Number	21308-80-5 Y
3D model (JSmol)	Interactive image
ChemSpider	10686917
PubChem CID	14513628
InChI InChI=1S/Br2O/c1-3-2 Key: HJCMMOODWZOXML-UHFFFAOYSA-N
SMILES O(Br)Br
Properties
Chemical formula	Br2O
Molar mass	175.807 g/mol
Appearance	dark brown solid
Melting point	decomposes around −17.5°C[1]
Related compounds
Related compounds	Water Oxygen difluoride Dichlorine monoxide Diiodine monoxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Reactions

Dibromine monoxide can be prepared by reacting bromine vapor or a solution of bromine in carbon tetrachloride with mercury(II) oxide at low temperatures:^[1][3]

2 Br₂ + 2 HgO → HgBr₂·HgO + Br₂O

It can also be formed by thermal decomposition of bromine dioxide^[2] or by passing an electrical current through a 1:5 mixture of bromine and oxygen gases.^[3]