Halide
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2008-06-08T11:15:02Z
Geonarva
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A '''halide''' is a [[binary compound]], of which one part is a [[halogen]] [[atom]] and the other part is an [[chemical element|element]] or [[radical (chemistry)|radical]] that is less [[electronegative]] than the halogen, to make a [[fluoride]], [[chloride]], [[bromide]], [[iodide]], or [[astatide]] compound. Many [[salt (chemistry)|salt]]s are halides. All Group 1 metals form halides with the halogens and they are white solids.
A '''halide ion''' is a halogen atom bearing a negative charge. The halide [[anion]]s are [[fluoride]] (F<sup>−</sup>), [[chloride]] (Cl<sup>−</sup>), [[bromide]] (Br<sup>−</sup>), [[iodide]] (I<sup>−</sup>) and [[astatide]] (At<sup>−</sup>). Such ions are present in all [[ionic bonding|ionic]] halide salts.
==Halides in organic chemistry==
In [[organic chemistry]] halides represent a [[functional group]]. Any organic compound that contains a halogen atom can be considered a halide. [[Alkyl halide]]s are organic compounds of the type R-X, containing an [[alkyl]] group R [[covalent]]ly bonded to a halogen X.
'''Pseudohalides''' resemble halides in their charge and reactivity; common examples are [[azide]]s NNN-, [[isocyanate]] -NCO, [[Isocyanide]], CN-, etc.<ref>{{GoldBookRef | title = pseudohalide | file = P04930 | year = 1995}}</ref>
A [[chemical test]] for the detection of halogen in chemical substances is the [[Carius halogen method]].
'''Dihalides''' are commonly used in the synthesis of cyclic alkanes.
== Test for Halide ions ==
Halide compounds such as KCl, KBr and KI can be tested with silver nitrate solution, AgNO<sub>3</sub>. The halogen will react with Ag<sup>+</sup> and form a [[precipitate]], with colour as follow:<br />
[[AgF]] - Yellowish Brown<br />
[[AgCl]] - White<br />
[[AgBr]] - Creamy (Pale Yellow)<br />
[[AgI]] - Yellow
== Halides in lighting ==
[[:Category:Metal halides|Metal halides]] are used in [[high-intensity discharge lamp]]s called [[metal halide lamp]]s, such as those used in modern [[street light]]s. These are more [[energy efficiency|energy-efficient]] than [[mercury-vapor lamp]]s, and have much better [[colour]] [[rendition]] than [[orange (colour)|orange]] [[Sodium-vapor lamp|high-pressure sodium lamps]]. Metal halide lamps are also commonly used in greenhouses or in rainy climates to supplement natural sunlight.
HID (High-intensity discharge) lamps however, contribute highly to [[light pollution]]. Sodium-vapor are favored for this reason.
==Halide compounds==
Examples of halide compounds are:
* [[sodium chloride]] (NaCl)
* [[potassium chloride]] (KCl)
* [[potassium iodide]] (KI)
* [[lithium chloride]] (LiCl)
* [[copper(II) chloride]] (CuCl<sub>2</sub>)
* [[chlorine fluoride]] (ClF)
* [[Bromomethane]] (CH<sub>3</sub>Br)
* [[Iodoform]] (CHI<sub>3</sub>)
* [[silver chloride]] (AgCl)
==See also==
*[[Salinity]]
*[[Functional groups]]
==References==
<references/>
[[Category:functional groups]]
[[Category:Salts]]
[[Category:Halides|*]]
[[bs:Halidi]]
[[ca:Halur]]
[[da:Halogenid]]
[[de:Halogenide]]
[[et:Halogeniid]]
[[es:Haluro]]
[[eo:Halogenido]]
[[eu:Haluro]]
[[fr:Halogénure]]
[[it:Alogenuro]]
[[mk:Халид]]
[[nl:Halogeniden]]
[[ja:ハロゲン化合物]]
[[pl:Halogenki]]
[[ru:Галогенид]]
[[sk:Halogenid]]
[[fi:Halidi]]
[[sv:Halogenider]]
[[zh:卤化物]]