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Names | |||
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IUPAC name
Ammonium ion
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Systematic IUPAC name
Azanium[1] | |||
Identifiers | |||
3D model (JSmol)
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ChEBI | |||
ChemSpider | |||
MeSH | D000644 | ||
PubChem CID
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UNII | |||
CompTox Dashboard (EPA)
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Properties | |||
[NH4]+ | |||
Molar mass | 18.039 g·mol−1 | ||
Acidity (pKa) | 9.25 | ||
Conjugate base | Ammonia | ||
Structure | |||
Tetrahedral | |||
Related compounds | |||
Other cations
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Related compounds
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Ammonium radical •NH4 | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Ammonium is a modified form of ammonia that has an extra hydrogen atom. It is a positively charged (cationic) molecular ion with the chemical formula NH+4 or [NH4]+. It is formed by the addition of a proton (a hydrogen nucleus) to ammonia (NH3). Ammonium is also a general name for positively charged (protonated) substituted amines and quaternary ammonium cations ([NR4]+), where one or more hydrogen atoms are replaced by organic or other groups (indicated by R). Not only is ammonium a source of nitrogen and a key metabolite for many living organisms, but it is an integral part of the global nitrogen cycle.[2] As such, human impact in recent years could have an effect on the biological communities that depend on it.