Selenium oxybromide (
Se O Br2) is a
selenium
Selenium is a chemical element; it has symbol (chemistry), symbol Se and atomic number 34. It has various physical appearances, including a brick-red powder, a vitreous black solid, and a grey metallic-looking form. It seldom occurs in this elem ...
oxohalide
In chemistry, oxohalides or oxyhalides are a group of chemical compounds with the chemical formula , where X is a halogen, and A is an element different than O and X. Known oxohalides have fluorine (F), chlorine (Cl), bromine (Br), and/or iodine ( ...
chemical compound
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...
.
Preparation
Selenium oxybromide can be prepared through the reaction of
selenium dioxide
Selenium dioxide is the chemical compound with the formula SeO2. This colorless solid is one of the most frequently encountered compounds of selenium. It is used in making specialized glasses as well as a reagent in organic chemistry.
Properties ...
and
selenium tetrabromide. Selenium and selenium dioxide are reacted with
bromine
Bromine is a chemical element; it has chemical symbol, symbol Br and atomic number 35. It is a volatile red-brown liquid at room temperature that evaporates readily to form a similarly coloured vapour. Its properties are intermediate between th ...
to form selenium monobromide and selenium tetrabromide. Dissolving the selenium dioxide in the tetrabromide will produce the oxybromide.
:2 Se + Br
2 → Se
2Br
2
:Se
2Br
2 + 3 Br
2 → 2 SeBr
4
:SeBr
4 + SeO
2 → 2 SeOBr
2
Structure
Evidence from
infrared
Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...
and
polarized Raman spectroscopy suggests that selenium oxybromide adopts a
pyramidal molecular geometry with
''C''s symmetry,
like other chalcogen(IV) oxohalides such as
thionyl bromide
Thionyl bromide is the chemical compound SOBr2. It is less stable and less widely used than its chloride analogue, thionyl chloride, but engages in similar reactions.
Chemistry
It is prepared by the action of hydrogen bromide on thionyl chloride ...
() and
selenium oxydichloride ().
Properties
Selenium oxybromide is a reddish-brown solid with a low melting point (41.6 °C) and chemical properties similar to
selenium oxychloride. It boils at 220 °C and decomposes near the boiling point, making distillation an ineffective purification method. Its
electrical conductivity
Electrical resistivity (also called volume resistivity or specific electrical resistance) is a fundamental specific property of a material that measures its electrical resistance or how strongly it resists electric current. A low resistivity in ...
in the liquid state just above the melting temperature is 6×10
−5 S/m. SeOBr
2 is
hydrolyzed
Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile.
Biological hydrolysi ...
by water to form
H2SeO3 and
HBr.
SeOBr
2 is highly reactive, with most reactions taking place in the liquid state. Selenium will dissolve in it, forming Se
2Br
2. Iron, copper, gold, platinum, and zinc are all attacked by SeOBr
2.
References
Selenium(IV) compounds
Oxobromides
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