View source for Selenide

{{Short description|Chemical compound containing selenium}}
A '''selenide''' is a chemical compound containing a [[selenium]] with [[oxidation number]] of −2.  Similar to [[sulfide]], selenides occur both as inorganic compounds and as organic derivatives, which are called [[organoselenium compound]].

==Inorganic selenides==
[[Image:Cadmium selenide.jpg|thumb|right|144px|Sample of cadmium selenide, a pigment.]]
The parent inorganic selenide is [[hydrogen selenide]] (H<sub>2</sub>Se).  It is a colorless, malodorous, toxic gas.  It dissolves in [[aqueous solution]], to give the hydrogenselenide or biselenide ion HSe<sup>−</sup>.  At higher pH, selenide forms.  Solutions of hydrogen selenide and selenide are oxidized by air to give elemental selenium:
:{{chem2|2 SeH-  +  O2  ->  2 Se  +  2 OH-}}

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]] but its use has been declining because of environmental considerations.  [[Copper indium selenide]] ({{chem2|CuInSe2}}) has attractive potential for photovoltaic devices, but these applications have not been implemented widely.<ref name=Ullmann/> Similarly, [[quantum dot]]s based on metal selenides have been extensively investigated for their distinctive spectral properties.<ref>{{Cite journal|title = Water-Soluble Quantum Dots for Multiphoton Fluorescence Imaging in Vivo|journal = Science|date = 2003-05-30|issn = 0036-8075|pmid = 12775841|pages = 1434–1436|volume = 300|issue = 5624|doi = 10.1126/science.1083780|language = en|first1 = Daniel R.|last1 = Larson|first2 = Warren R.|last2 = Zipfel|first3 = Rebecca M.|last3 = Williams|first4 = Stephen W.|last4 = Clark|first5 = Marcel P.|last5 = Bruchez|first6 = Frank W.|last6 = Wise|first7 = Watt W.|last7 = Webb|bibcode = 2003Sci...300.1434L| s2cid=7968711 }}</ref> Core-shell alloys of [[cadmium sulfide]] and selenide are of interest in imaging and [[phototherapy]].<ref>{{Cite journal|title = Copper Selenide Nanocrystals for Photothermal Therapy|journal = Nano Letters|date = 2011-06-08|issn = 1530-6984|pmc = 3111000|pmid = 21553924|pages = 2560–2566|volume = 11|issue = 6|doi = 10.1021/nl201400z|first1 = Colin M.|last1 = Hessel|first2 = Varun P.|last2 = Pattani|first3 = Michael|last3 = Rasch|first4 = Matthew G.|last4 = Panthani|first5 = Bonil|last5 = Koo|first6 = James W.|last6 = Tunnell|first7 = Brian A.|last7 = Korgel|bibcode = 2011NanoL..11.2560H}}</ref>

Many [[selenide mineral]]s are known.  Usually selenium partially [[Substitution (chemistry)|substitute]]s for sulfide in many [[sulfide mineral]]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]]<ref name=Ullmann>{{cite book|doi=10.1002/14356007.a23_525|chapter=Selenium and Selenium Compounds |title=Ullmann's Encyclopedia of Industrial Chemistry |year=2000 |last1=Langner |first1=Bernd E. |isbn=3527306730 }}</ref>

== Organic and biological selenides ==
{{main|organoselenium chemistry}}
Selenides are common in organic chemistry. They have two Se-C bonds, akin to organic sulfides. Examples include [[dimethyl selenide]], [[selenomethionine]], and [[Se-methylselenocysteine|''Se''-methylselenocysteine]].  Such compounds have few applications.

==Examples==
* [[Gallium(II) selenide]]
* [[Indium(III) selenide]]
* [[Lead selenide]]
* [[Copper selenide]]

== See also ==
* [[Sulfoselenide]]

==References ==
{{reflist|30em}}

==External links==
* [https://www.sciencedaily.com/releases/2002/08/020809071535.htm Selenide Nanoparticles Used In Solar Energy Conversion].

{{Selenides}}
{{Monatomic anion compounds}}
{{Authority control}}

[[Category:Selenides| ]]
[[Category:Chalcogenides]]
[[Category:Solar cells]]
[[Category:Selenium(−II) compounds]]