A selenide is a chemical compound containing 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 ...
with
oxidation number of −2. Similar to
sulfide
Sulfide (also sulphide in British English) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to large families o ...
, selenides occur both as inorganic compounds and as organic derivatives, which are called
organoselenium compound.
Inorganic selenides
The parent inorganic selenide is
hydrogen selenide (H
2Se). It is a colorless, malodorous, toxic gas. It dissolves in
aqueous solution, to give the hydrogenselenide or biselenide ion HSe
−. At higher pH, selenide forms. Solutions of hydrogen selenide and selenide are oxidized by air to give elemental selenium:
:
Most elements form selenides. They sometimes have salt-like properties, e.g.
sodium selenide, but most exhibit covalent bonding, e.g.
molybdenum diselenide. Their properties are diverse, mirroring the diverse properties of the corresponding sulfides.
As indicated by the fact that only a few thousand tons of selenium are produced annually, the subset of selenium compounds called selenides find few applications. Commercially significant is
zinc selenide, which is used in some infrared optics.
Cadmium selenide is a
pigment
A pigment is a powder used to add or alter color or change visual appearance. Pigments are completely or nearly solubility, insoluble and reactivity (chemistry), chemically unreactive in water or another medium; in contrast, dyes are colored sub ...
but its use has been declining because of environmental considerations.
Copper indium selenide () has attractive potential for photovoltaic devices, but these applications have not been implemented widely.
[ Similarly, quantum dots based on metal selenides have been extensively investigated for their distinctive spectral properties. Core-shell alloys of cadmium sulfide and selenide are of interest in imaging and phototherapy.]sulfide mineral
The sulfide minerals are a class of minerals containing sulfide (S2−) or disulfide () as the major anion. Some sulfide minerals are economically important as metal ores. The sulfide class also includes the selenide mineral, selenides, the tell ...
s. The degree of substitution is only of commercial interest for copper sulfide ores, in which case selenium is recovered as a by-product of copper refining. Some selenide minerals include ferroselite and umangite
Organic and biological selenides
Selenides are common in organic chemistry. They have two Se-C bonds, akin to organic sulfides. Examples include dimethyl selenide, selenomethionine, and ''Se''-methylselenocysteine. Such compounds have few applications.
Examples
* Gallium(II) selenide
* Indium(III) selenide
* Lead selenide
* Copper selenide
See also
* Sulfoselenide
References
External links
Selenide Nanoparticles Used In Solar Energy Conversion
{{Authority control
Chalcogenides
Solar cells
Selenium(−II) compounds