A ball-and-stick model of the ammonium cation

Ammonium is also an old name for the Siwa Oasis in western Egypt.

The ammonium cation is a positively charged polyatomic cation of the chemical formula NH₄⁺. It has a molecular mass of 18.04 and is formed by protonation of ammonia (NH₃). The resulting ion has a pK_a of 9.25. Ammonium and aminium are also general names for positively charged or protonated substituted amines and quaternary ammonium cations N⁺R₄, where one or more hydrogen atoms are replaced by organic radical groups (which could be symbolized as R). Image File history File links Download high-resolution version (1100x1077, 157 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Ammonium ... Image File history File links Download high-resolution version (1100x1077, 157 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Ammonium ... armchair conformational isomerism of Cyclohexane. ... The Siwa Oasis is an oasis in Egypt, located between the Qattara Depression and the Egyptian Sand Sea in the Libyan Desert. ... A cation is an ion with positive charge. ... Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. ... An electrostatic potential map of the nitrate ion (NO3−). Areas coloured red are lower in energy than areas coloured yellow A polyatomic ion is a molecule that bears ionic groups, that is, a molecule with a charge. ... A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... The molecular mass (abbreviated Mr) of a substance, formerly also called molecular weight and abbreviated as MW, is the mass of one molecule of that substance, relative to the unified atomic mass unit u (equal to 1/12 the mass of one atom of carbon-12). ... Protonation is the addition of a proton (H+) to an atom, molecule, or ion. ... For other uses, see Ammonia (disambiguation). ... The acid dissociation constant (Ka), also known as the acidity constant or the acid-ionization constant, is a specific equilibrium constant for the reaction of an acid with its conjugate base in aqueous solution [1]. // When an acid dissolves in water, it partly dissociates forming hydronium ions and its conjugate... Protonation is the addition of a proton (H+) to an atom, molecule, or ion. ... Look up substitution in Wiktionary, the free dictionary. ... The general structure of an amine Amines are organic compounds and a type of functional group that contain nitrogen as the key atom. ... Categories: Chemistry stubs ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... Properties For alternative meanings see atom (disambiguation). ... An alkane in organic chemistry is a type of hydrocarbon in which the molecule has the maximum possible number of hydrogen atoms and so has no double bonds (they are saturated). ...

Chemistry

Fumes from hydrochloric acid and ammonia forming a white cloud of ammonium chloride

The lone electron pair on the nitrogen (N) in ammonia is represented as a pair of dots. This electron pair forms the bond with a proton H⁺.

In an ammonium ion, the positively charged nitrogen atom forms four covalent bonds, instead of three as in ammonia. This reaction is reversible. The ammonium ion can act as a very weak Brønsted-Lowry acid in the sense that it can protonate a stronger base using any one of its hydrogen ( H ) atoms and convert back to ammonia. This means that the ammonium ion is a conjugate acid of the base ammonia. In a solution, the degree to which ammonia forms the ammonium ion depends on the pH of the solution. Image File history File links Open tube of ammonia fumes when held near open beaker of hydrochloric acid File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Open tube of ammonia fumes when held near open beaker of hydrochloric acid File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Ammonium chloride or Sal Ammoniac (chemically ammonium chloride (NH4Cl); also salmiac, nushadir salt, zalmiak, sal armagnac, sal armoniac, salmiakki, salmiak and salt armoniack) is, in its pure form, a clear white water-soluble crystalline salt with a biting, slightly sour taste. ... Image File history File links This image is identical to one by the same name Commons:Image:Neutralization of Ammonia. ... Image File history File links This image is identical to one by the same name Commons:Image:Neutralization of Ammonia. ... A lone pair is an electron pair without bonding or sharing with other atoms. ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... For other uses, see Proton (disambiguation). ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... Covalent redirects here. ... For other uses, see Chemical reaction (disambiguation). ... A weak acid is an acid that does not fully ionize in solution; that is, if the acid was represented by the general formula HA, then in aqueous solution a significant amount of undissolved HA still remains. ... In chemistry, the Brønsted-Lowry system defines acids and alkalis. ... Acids and bases: Acid-base extraction Acid-base reaction Acid dissociation constant Acidity function Buffer solutions pH Proton affinity Self-ionization of water Acids: Lewis acids Mineral acids Organic acids Strong acids Superacids Weak acids Bases: Lewis bases Organic bases Strong bases Superbases Non-nucleophilic bases Weak bases edit In... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... Within the Brønsted-Lowry (protonic) theory of acids and bases, a conjugate acid is the acid member, HX, of a pair of two compounds that transform into each other by gain or loss of a proton. ... Making a saline water solution by dissolving table salt (NaCl) in water This article is about chemical solutions. ... For other uses, see PH (disambiguation). ...

However, formation of ammonium compounds can also occur in the vapor phase; for example, when ammonia vapor comes in contact with hydrogen chloride vapor, a white cloud of ammonium chloride forms, which eventually settles out as a solid in a thin white layer on surfaces. Ammonium cations resemble alkali metal ions like Na⁺ or K⁺ and can be found in salts such as ammonium bicarbonate, ammonium chloride, and ammonium nitrate. Most simple ammonium salts are very water soluble. Ammonium ions are a toxic waste product of the metabolism in animals and are excreted unchanged in the urine by water animals. The ammonium ion behaves somewhat like an alkali metal ion. This article is about the chemical use. ... For other uses, see Solid (disambiguation). ... The alkali metals are a series of elements comprising Group 1 (IUPAC style) of the periodic table: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). ... This article is about the electrically charged particle. ... For sodium in the diet, see Edible salt. ... General Name, symbol, number potassium, K, 19 Chemical series alkali metals Group, period, block 1, 4, s Appearance silvery white Standard atomic weight 39. ... For other uses, see Salt (disambiguation). ... Ammonium bicarbonate (also called bicarbonate of ammonia, ammonium hydrogen carbonate, hartshorn, or powdered baking ammonia) is the bicarbonate salt of ammonia. ... Ammonium chloride or Sal Ammoniac (chemically ammonium chloride (NH4Cl); also salmiac, nushadir salt, zalmiak, sal armagnac, sal armoniac, salmiakki, salmiak and salt armoniack) is, in its pure form, a clear white water-soluble crystalline salt with a biting, slightly sour taste. ... Related Compounds Other anions Ammonium nitrite; ammonium perchlorate Other cations Sodium nitrate; potassium nitrate; hydroxylammonium nitrate Related compounds Nitrous oxide Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references The chemical compound ammonium nitrate, the nitrate of... It has been suggested that this article or section be merged with Solution. ... Toxic redirects here, but this is also the name of a song by Britney Spears; see Toxic (song) Look up toxic and toxicity in Wiktionary, the free dictionary. ... Structure of the coenzyme adenosine triphosphate, a central intermediate in energy metabolism. ... For other uses, see Animal (disambiguation). ... This article or section is in need of attention from an expert on the subject. ... This article is about the electrically charged particle. ... The alkali metals are a series of elements comprising Group 1 (IUPAC style) of the periodic table: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). ...

At attempt of reception of metal ammonium the ion, receiving electron, breaks up to ammonia and hydrogen:

2NH₄⁺ + 2e⁻ = 2NH₃ + H₂

Ammonium ions may dissolve in mercury^[1] to form an amalgam. General Name, Symbol, Number mercury, Hg, 80 Chemical series transition metals Group, Period, Block 12, 6, d Appearance silvery Standard atomic weight 200. ... This article is about mixtures (alloys) of mercury with other elements. ...

Substituted ammonium ions

Any hydrogen in the ammonium ion can be substituted with an alkyl (or other organic radical) group to form a substituted ammonium ion, also called aminium ion; see amine for details. Depending on the number of organic radical groups, it is called a primary, a secondary, a tertiary, or a quaternary ammonium cation. They exist in an equilibrium with the respective substituted amine,depending on the pH. Only quaternary ammonium cations are permanently charged. The general structure of an amine Amines are organic compounds and a type of functional group that contain nitrogen as the key atom. ... Categories: Chemistry stubs ... For other uses, see PH (disambiguation). ...

An example of a reaction forming an ammonium ion is that between dimethylamine, (CH₃)₂NH, with an acid to give the dimethylaminium cation, (CH₃)₂NH₂⁺: Safety (MSDS) data for dimethylamine General Synonyms: N-methyl-methanamine Molecular formula: C2H7N CAS No: 124-40-3 EINECS No: 204-697-4 EC index no: 612-001-00-9 Physical data Appearance: colourless gas with strong ammonia-like smell Melting point: -92 C Boiling point: 7. ...

Image File history File links Download high-resolution version (1100x330, 17 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Ammonium ...

See also

• f-ratio
• Hydronium (H₃O⁺)
• Nitrification
• Quaternary ammonium cation (R₄N⁺)
• Onium compounds

In oceanic biogeochemistry, the f-ratio is the fraction of total primary production fuelled by nitrate (as opposed to that fuelled by other nitrogen compounds such as ammonium). ... In chemistry, hydronium is the common name for the cation H3O+ derived from protonation of water. ... Nitrogen cycle Nitrification is the biological oxidation of ammonia with oxygen into nitrite followed by the oxidation of these nitrites into nitrates. ... Categories: Chemistry stubs ... Onium compounds are cations derived by the protonation of mononuclear parent hydrides of elements of Groups V, VI and VII, and similar ions derived by the substitution of hydrogen atoms in the former by other groups, such as organic radicals, or halogens, including not only ions such as tetramethylammonium, but...

References

1. ^ Pseudo-binary compounds