Ammonium

Ammonium
2-D skeletal version of the ammonium ion
Ball-and-stick model of the ammonium cation
Space-filling model of the ammonium cation
Names
IUPAC name
Ammonium ion
Systematic IUPAC name
Azanium[1]
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
MeSH D000644
UNII
  • InChI=1S/H3N/h1H3/p+1
    Key: QGZKDVFQNNGYKY-UHFFFAOYSA-O
  • InChI=1/H3N/h1H3/p+1
    Key: QGZKDVFQNNGYKY-IKLDFBCSAZ
  • [NH4+]
Properties
[NH4]+
Molar mass 18.039 g·mol−1
Acidity (pKa) 9.25
Conjugate base Ammonia
Structure
Tetrahedral
Related compounds
Other cations
Related compounds
Ammonium radical •NH4
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

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.

  1. ^ International Union of Pure and Applied Chemistry (2005). Nomenclature of Inorganic Chemistry (IUPAC Recommendations 2005). Cambridge (UK): RSCIUPAC. ISBN 0-85404-438-8. pp. 71,105,314. Electronic version.
  2. ^ Schlesinger, William H.; Bernhardt, Emily S. (2020-01-01), Schlesinger, William H.; Bernhardt, Emily S. (eds.), "Chapter 12 - The Global Cycles of Nitrogen, Phosphorus and Potassium", Biogeochemistry (Fourth Edition), Academic Press, pp. 483–508, doi:10.1016/b978-0-12-814608-8.00012-8, ISBN 978-0-12-814608-8, retrieved 2024-03-08