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**Chemical Properties of Ammonium:**
Ammonium ion is generated from ammonia in the presence of Brønsted acids.
– It is mildly acidic and can react with bases to form uncharged ammonia.
– Equilibrium between ammonia and ammonium ions depends on solution pH.
– Treatment of ammonium salts with a strong base yields ammonia.
Ammonium cation is found in salts like ammonium carbonate, chloride, and nitrate.
Ammonium salts exhibit characteristic reactions, such as releasing ammonia gas when heated with alkali hydroxide.
– The lone electron pair on nitrogen in ammonia forms a coordinate bond with a proton.
– The size and structure of the ammonium cation are similar to the caesium cation.
Ammonium cation has polar covalent bonds.

**Organic Ammonium Compounds:**
Ammonium ions can be substituted with organic groups to form various types of ammonium ions.
– Different organic groups determine the classification of ammonium cations as primary, secondary, tertiary, or quaternary.
– Quaternary ammonium cations are devoid of a hydrogen atom and are used to enhance solubility in organic solvents.
– Various types of organic ammonium salts serve as phase-transfer catalysts and surfactants.
– Organic ammonium salts include derivatives of amine radical cations.

**Biological Role and Environmental Impact of Ammonium:**
Ammonium ions are waste products in animal metabolism.
– Plants utilize ammonium as a nitrogen source, but it can be toxic to most crop species.
Fish excrete ammonium directly into water, while mammals convert it to urea.
– Birds and reptiles convert metabolic ammonium into uric acid.
Ammonium runoff from fertilizers can contribute to water pollution.

**Industrial Applications and Preparation of Ammonium:**
Ammonium is synthesized by reacting ammonia with acids.
– The Haber process is a common industrial method for ammonium production.
Ammonium is essential in agriculture as a nutrient for plants.
– It is used in fertilizers, cleaning products, chemical manufacturing, pharmaceuticals, textiles, and the food industry.
– Laboratory preparation involves mixing ammonia with a strong acid to form ammonium salts.

**Safety and Reactions Involving Ammonium:**
Ammonium compounds can be toxic if ingested and corrosive to the skin.
– Inhalation of ammonia gas from ammonium compounds can irritate the respiratory system.
– Storage precautions include keeping ammonium away from oxidizing agents.
Ammonium reacts in various ways, including forming salts in acid-base reactions, releasing ammonia gas upon heating, burning in the presence of oxygen, and complexing with transition metals.

Ammonium (Wikipedia)

The ammonium cation is a positively charged polyatomic ion with the chemical formula NH+4 or [NH4]+. It is formed by the protonation of 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).

2-D skeletal version of the ammonium ion
Ball-and-stick model of the ammonium cation
Space-filling model of the ammonium cation
IUPAC name
Ammonium ion
Systematic IUPAC name
3D model (JSmol)
MeSH D000644
  • InChI=1S/H3N/h1H3/p+1
  • InChI=1/H3N/h1H3/p+1
  • [NH4+]
Molar mass 18.039 g·mol−1
Acidity (pKa) 9.25
Conjugate base Ammonia
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).
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