Selenium oxybromide (
Se O Br2) is a
selenium
Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, ...
oxohalide
In chemistry, molecular oxohalides (oxyhalides) are a group of chemical compounds in which both oxygen and halogen atoms are attached to another chemical element A in a single molecule. They have the general formula , where X = fluorine (F), ch ...
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.
Properties
Solid SeO2 is a one-dimensional polymer, the chain consisting of alternating seleniu ...
and
selenium tetrabromide. Selenium and selenium dioxide are reacted with
bromine
Bromine is a chemical element with the symbol Br and atomic number 35. It is the third-lightest element in group 17 of the periodic table ( halogens) and is a volatile red-brown liquid at room temperature that evaporates readily to form a simi ...
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 those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
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 () 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 in the liquid state just above the melting temperature is 6×10
−5 S/m. SeOBr
2 is
hydrolyzed 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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