Hydrogen ion
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2008-04-04T15:59:20Z
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/* Anion (negatively charged) */ added "See also"
'''Hydrogen ion''' is recommended by [[IUPAC]] as a general term for all [[ion]]s of [[hydrogen]] and its [[isotope]]s.<ref>''Compendium of Chemical Terminology'', 2nd edition McNaught, A.D. and Wilkinson, A. Blackwell Science, 1997 [ISBN 0-86542-684-8], also [http://www.iupac.org/publications/compendium/index.html online]</ref> Depending on the [[charge]] of the ion, two different classes can be distinguished:
==Cation (positively charged)==
When hydrogen loses its [[electron]], the following [[cation]]s can be formed:
* [[Hydron (chemistry)|Hydron]]: general name referring to the positive ion of any hydrogen isotope (H<sup>+</sup>)
* [[Proton]]: <sup>1</sup>H<sup>+</sup>
* [[Deuteron]]: <sup>2</sup>H<sup>+</sup>, D<sup>+</sup>
* Triton: <sup>3</sup>H<sup>+</sup>, T<sup>+</sup>
In addition, the ions produced by the reaction of these cations with [[water]] as well as their [[hydrates]] are called hydrogen ions:
* [[Hydronium]] ion: H<sub>3</sub>O<sup>+</sup>
* '''Zundel cation''': H<sub>5</sub>O<sub>2</sub><sup>+</sup>
* '''Eigen cation''': H<sub>9</sub>O<sub>4</sub><sup>+</sup>
The latter two play an important role in proton hopping according to the [[Grotthuss mechanism]].
In connection with acids, hydrogen ions typically refer to [[Hydron (chemistry)|hydrons]].
==Anion (negatively charged)==
Hydrogen [[anion]]s are formed when additional electrons are acquired:
* [[Hydride]]: general name referring to the negative ion of any hydrogen isotope
* Deuteride: <sup>2</sup>H<sup>-</sup>, D<sup>-</sup>
* Tritide: <sup>3</sup>H<sup>-</sup>, T<sup>-</sup>
In [[organic chemistry]], a hydrogen atom in a molecule is often referred to simply as a proton. The [[hydrogen anion]] has played an important role in quantum physics.
==See also==
* [[Acid]]
* [[PH|pH]]
==References==
{{reflist}}
[[Category:Hydrogen physics]]
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