In chemistry, an onium ion is a

cation An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

formally obtained by the

protonation In chemistry, protonation (or hydronation) is the adding of a proton (or hydron, or hydrogen cation), (H+) to an atom, molecule, or ion, forming a conjugate acid. (The complementary process, when a proton is removed from a Brønsted–Lowry acid ...

of mononuclear parent

hydride In chemistry, a hydride is formally the anion of hydrogen( H−). The term is applied loosely. At one extreme, all compounds containing covalently bound H atoms are called hydrides: water (H2O) is a hydride of oxygen, ammonia is a hydride of ...

of a

pnictogen A pnictogen ( or ; from grc, πνῑ́γω "to choke" and -gen, "generator") is any of the chemical elements in group 15 of the periodic table. Group 15 is also known as the nitrogen group or nitrogen family. Group 15 consists of the el ...

(group 15 of the

periodic table The periodic table, also known as the periodic table of the (chemical) elements, is a rows and columns arrangement of the chemical elements. It is widely used in chemistry, physics, and other sciences, and is generally seen as an icon of ...

chalcogen The chalcogens (ore forming) ( ) are the chemical elements in group 16 of the periodic table. This group is also known as the oxygen family. Group 16 consists of the elements oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and the radioa ...

(group 16), or halogen (group 17). The oldest-known onium ion, and the namesake for the class, is

ammonium The ammonium cation is a positively-charged polyatomic ion with the chemical formula or . It is formed by the protonation of ammonia (). Ammonium is also a general name for positively charged or protonated substituted amines and quaternar ...

, , the protonated derivative of

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogeno ...

, . The name onium is also used for cations that would result from the substitution of hydrogen atoms in those ions by other groups, such as organic radicals, or halogens; such as tetraphenylphosphonium, . The substituent groups may be divalent or trivalent, yielding ions such as iminium and nitrilium. A simple onium ion has a charge of +1. A larger ion that has two onium ion subgroups is called a double onium ion, and has a charge of +2. A triple onium ion has a charge of +3, and so on. Compounds of an onium cation and some other

anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

are known as onium compounds or onium salts. Onium ions and onium compounds are inversely

analog Analog or analogue may refer to: Computing and electronics * Analog signal, in which information is encoded in a continuous variable ** Analog device, an apparatus that operates on analog signals *** Analog electronics, circuits which use analo ...

ous to ions and ate complexes: * Lewis bases form onium ions when the central atom gains one more bond and becomes a positive

. *Lewis acids form ions when the central atom gains one more bond and becomes a negative

Simple onium cations (hydrides with no substitutions)

Group 13 The Group 13 network ( pl, Trzynastka, Yiddish: ''דאָס דרײַצענטל'') was a Jewish Nazi collaborationist organization in the Warsaw Ghetto during the German occupation of Poland in World War II. The rise and fall of the Gro ...
(boron group) onium cations

* boronium cation, (protonated

borane Trihydridoboron, also known as borane or borine, is an unstable and highly reactive molecule with the chemical formula . The preparation of borane carbonyl, BH3(CO), played an important role in exploring the chemistry of boranes, as it indicated ...

) **further boronium cations, (protonated

boranes Boranes is the name given to compounds with the formula BxHy and related anions. Many such boranes are known. Most common are those with 1 to 12 boron atoms. Although they have few practical applications, the boranes exhibit structures and bon ...

)

Group 14 (carbon group) onium cations

* carbonium ions (protonated

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...

s) have a pentavalent carbon atom with a +1 charge. **alkanium cations, (protonated

alkane In organic chemistry Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms tha ...

s) *** methanium, (protonated

methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Ear ...

) (Sometimes called carbonium, because it is the simplest member of that class, but that use is deprecated because of multiple definitions. Sometimes called methonium, but methonium also has multiple definitions. Abundant in outer space.) *** ethanium, (protonated

ethane Ethane ( , ) is an organic chemical compound with chemical formula . At standard temperature and pressure, ethane is a colorless, odorless gas. Like many hydrocarbons, ethane is isolated on an industrial scale from natural gas and as a petro ...

) *** propanium, (

propane Propane () is a three-carbon alkane with the molecular formula . It is a gas at standard temperature and pressure, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as ...

protonated on an unspecified carbon) **** propylium, or propan-1-ylium (propane protonated on an end carbon) **** propan-2-ylium (propane protonated on the middle carbon) *** butanium, (

butane Butane () or ''n''-butane is an alkane with the formula C4H10. Butane is a gas at room temperature and atmospheric pressure. Butane is a highly flammable, colorless, easily liquefied gas that quickly vaporizes at room temperature. The name bu ...

protonated on an unspecified carbon) **** ''n''-butanium ( ''n''-butane protonated on an unspecified carbon) ***** ''n''-butylium, or ''n''-butan-1-ylium (''n''-butane protonated on an end carbon) ***** ''n''-butan-2-ylium (n-butane protonated on a middle carbon) **** isobutanium ( isobutane protonated on an unspecified carbon) ***** isobutylium, or isobutan-1-ylium (isobutane protonated on an end carbon) ***** isobutan-2-ylium (isobutane protonated on the middle carbon) *** octonium or octanium, (protonated octane) * silanium (sometimes silonium), (protonated

silane Silane is an inorganic compound with chemical formula, . It is a colourless, pyrophoric, toxic gas with a sharp, repulsive smell, somewhat similar to that of acetic acid. Silane is of practical interest as a precursor to elemental silicon. Sila ...

) (should not be called siliconiumRC-82. Cations
Queen Mary University of London) ** disilanium, (protonated disilane) **further silanium cations, (protonated silanes) * germonium, (protonated germane) * stannonium, (protonated ) (not protonated stannane ) * plumbonium, (protonated )

Group 15 (pnictogen) onium cations

(

IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. It is ...

name azanium), (protonated

(IUPAC name azane)) * phosphonium, (protonated

phosphine Phosphine ( IUPAC name: phosphane) is a colorless, flammable, highly toxic compound with the chemical formula , classed as a pnictogen hydride. Pure phosphine is odorless, but technical grade samples have a highly unpleasant odor like rotti ...

) *

arsonium The arsonium cation is a positively charged polyatomic ion with the chemical formula . An arsonium salt is a salt containing either the arsonium () cation, such as arsonium bromide () and arsonium iodide (), which can be synthesized by reacting ...

, (protonated

arsine Arsine ( IUPAC name: arsane) is an inorganic compound with the formula As H3. This flammable, pyrophoric, and highly toxic pnictogen hydride gas is one of the simplest compounds of arsenic. Despite its lethality, it finds some applications in ...

) * stibonium, (protonated

stibine Stibine (IUPAC name: stibane) is a chemical compound with the formula SbH3. A pnictogen hydride, this colourless, highly toxic gas is the principal covalent hydride of antimony, and a heavy analogue of ammonia. The molecule is pyramidal with H–S ...

) * bismuthonium, (protonated

bismuthine Bismuthine (IUPAC name: bismuthane) is the chemical compound with the formula BiH3. As the heaviest analogue of ammonia (a pnictogen hydride), BiH3 is unstable, decomposing to bismuth metal well below 0 °C. This compound adopts the expe ...

)

Group 16 (chalcogen) onium cations

* oxonium, (protonated

water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as ...

(IUPAC name oxidane). Oxonium is better known as

hydronium In chemistry, hydronium (hydroxonium in traditional British English) is the common name for the aqueous cation , the type of oxonium ion produced by protonation of water. It is often viewed as the positive ion present when an Arrhenius acid is di ...

, though hydronium implies a solvated or hydrated proton. It may also be called hydroxonium.) * sulfonium, (protonated

hydrogen sulfide Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. The und ...

) * selenonium, (protonated hydrogen selenide) * telluronium, (protonated hydrogen telluride)

Group 17 (halogen) onium cations, halonium ions, H₂X⁺ (protonated
hydrogen halide In chemistry, hydrogen halides (hydrohalic acids when in the aqueous phase) are diatomic, inorganic compounds that function as Arrhenius acids. The formula is HX where X is one of the halogens: fluorine, chlorine, bromine, iodine, or astati ...
s)

* fluoronium, (protonated hydrogen fluoride) * chloronium, (protonated

hydrogen chloride The compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colourless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chloride g ...

) * bromonium, (protonated hydrogen bromide) * iodonium, (protonated hydrogen iodide)

Pseudohalogen onium cations

* aminodiazonium, (protonated hydrogen azide) *methylidyneammonium/hydrocyanonium, , isomers HC≡NH⁺ and N≡CH (protonated

hydrogen cyanide Hydrogen cyanide, sometimes called prussic acid, is a chemical compound with the formula HCN and structure . It is a colorless, extremely poisonous, and flammable liquid that boils slightly above room temperature, at . HCN is produced on a ...

)

Group 18 (noble gas) onium cations

* hydrohelium or helonium, better known as helium hydride ion, HeH⁺ (protonated

helium Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. ...

) * neonium, NeH⁺ (protonated

neon Neon is a chemical element with the symbol Ne and atomic number 10. It is a noble gas. Neon is a colorless, odorless, inert monatomic gas under standard conditions, with about two-thirds the density of air. It was discovered (along with krypt ...

) * argonium, ArH⁺ (protonated

argon Argon is a chemical element with the symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third-most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as a ...

) *

kryptonium Kryptonite is a fictional material that appears primarily in Superman stories published by DC Comics. In its best-known form, it is a green, crystalline material originating from Superman's home world of Krypton (comics), Krypton that emits a u ...

, KrH⁺ (protonated

krypton Krypton (from grc, κρυπτός, translit=kryptos 'the hidden one') is a chemical element with the symbol Kr and atomic number 36. It is a colorless, odorless, tasteless noble gas that occurs in trace amounts in the atmosphere and is often ...

) *

xenonium The xenonium ion, XeH+, is an onium compound, consisting of protonated xenon. Although the existence of the xenonium cation itself has not been proven, salts of the fluoroxenonium ion, XeF+, are known to exist, for instance fluoroxenonium pentafluo ...

, XeH⁺ (protonated

xenon Xenon is a chemical element with the symbol Xe and atomic number 54. It is a dense, colorless, odorless noble gas found in Earth's atmosphere in trace amounts. Although generally unreactive, it can undergo a few chemical reactions such as the ...

) *trifluoroxenonium, ( is neutral.)

Hydrogen onium cation

*hydrogenonium, better known as trihydrogen cation, H (protonated molecular or diatomic

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...

), found in ionized hydrogen and interstellar space

Onium cations with monovalent substitutions

*primary ammonium cations, RH₃N⁺ or RNH (protonated primary

amine In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen atoms have been replaced by a substituent su ...

s) ** hydroxylammonium, NH₃OH⁺ (protonated hydroxylamine) ** methylammonium, CH₃NH (protonated

methylamine Methylamine is an organic compound with a formula of . This colorless gas is a derivative of ammonia, but with one hydrogen atom being replaced by a methyl group. It is the simplest primary amine. Methylamine is sold as a solution in methanol, ...

) ** ethylammonium, C₂H₅NH (protonated ethylamine) ** hydrazinium, or diazanium, NH₂NH (protonated

hydrazine Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly toxic unless handled in solution as, for example, hydrazin ...

, a.k.a. diazane) **anilinium (a.k.a. phenylammonium), (protonated

aniline Aniline is an organic compound with the formula C6 H5 NH2. Consisting of a phenyl group attached to an amino group, aniline is the simplest aromatic amine. It is an industrially significant commodity chemical, as well as a versatile start ...

, a.k.a. phenylamine, aminobenzene) *secondary ammonium cations, R₂NH (protonated secondary

s) ** dimethylammonium (sometimes dimethylaminium), (CH₃)₂NH (protonated dimethylamine) ** diethylammonium (sometimes diethylaminium), (C₂H₅)₂NH (protonated diethylamine) ** ethylmethylammonium, C₂H₅CH₃NH (protonated

ethylmethylamine Ethylmethylamine, or ''N''-methylethanamine, is a compound with the chemical formula C3H9N. It is corrosive and highly flammable A combustible material is something that can burn (i.e., ''combust'') in air. A combustible material is flamma ...

) ** diethanolammonium (sometimes diethanolaminium), (C₂H₄OH)₂NH (protonated diethanolamine) *tertiary ammonium cations, R₃NH⁺ (protonated tertiary

s) **

trimethylammonium Trimethylamine (TMA) is an organic compound with the formula N(CH3)3. It is a colorless, hygroscopic, and flammable tertiary amine. It is a gas at room temperature but is usually sold as a 40% solution in water. (It is also sold in pressurized g ...

(CH₃)₃NH⁺ (protonated

trimethylamine Trimethylamine (TMA) is an organic compound with the formula N(CH3)3. It is a colorless, hygroscopic, and flammable tertiary amine. It is a gas at room temperature but is usually sold as a 40% solution in water. (It is also sold in pressurized ...

) ** triethylammonium (C₂H₅)₃NH⁺ (protonated

triethylamine Triethylamine is the chemical compound with the formula N(CH2CH3)3, commonly abbreviated Et3N. It is also abbreviated TEA, yet this abbreviation must be used carefully to avoid confusion with triethanolamine or tetraethylammonium, for which TEA ...

) * quaternary ammonium cations, R₄N⁺ or NR ** tetrafluoroammonium, NF ** tetramethylammonium, (CH₃)₄N⁺ **

tetraethylammonium Tetraethylammonium (TEA), () or (Et4N+) is a quaternary ammonium cation consisting of four ethyl groups attached to a central nitrogen atom, and is positively charged. It is a counterion used in the research laboratory to prepare lipophilic salts ...

, (C₂H₅)₄N⁺ ** tetrapropylammonium, (C₃H₇)₄N⁺ ** tetrabutylammonium, (C₄H₉)₄N⁺ or abbreviated Bu₄N⁺ ** trimethyl ammonium compounds, (CH₃)₃RN⁺ **

didecyldimethylammonium Didecyldimethylammonium chloride (DDAC) is a quaternary ammonium compound used as antiseptic/disinfectant. It causes the disruption of intermolecular interactions and the dissociation of lipid bilayers. The bacteriostatic (prevent growth) or ba ...

, (C₁₀H₂₁)₂(CH₃)₂N⁺ ** pentamethylhydrazinium, N(CH₃)₂N(CH₃) *quaternary phosphonium cations, R₄P⁺ or PR ** tetraphenylphosphonium, *primary oxonium cations, (protonated R-O-H oxygen compounds) **alkyloxonium cations (protonated

alcohols In chemistry, an alcohol is a type of organic compound that carries at least one hydroxyl () functional group bound to a saturated carbon atom. The term ''alcohol'' originally referred to the primary alcohol ethanol (ethyl alcohol), which i ...

) ***methyloxonium, (protonated methanol) ***ethyloxonium, (protonated

ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a h ...

) *secondary oxonium cations, (protonated R-O-R oxygen compounds) **dialkyloxonium cations (protonated

ether In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again b ...

s) ***dimethyloxonium, (protonated

dimethyl ether Dimethyl ether (DME; also known as methoxymethane) is the organic compound with the formula CH3OCH3, (sometimes ambiguously simplified to C2H6O as it is an isomer of ethanol). The simplest ether, it is a colorless gas that is a useful precurs ...

) *tertiary oxonium cations, ** trifluorooxonium, (hypothetical) ** trimethyloxonium, ** triethyloxonium, **

oxatriquinacene Oxatriquinacene is an organic cation with formula . It is an oxonium ion, with a trivalent oxygen atom with +1 charge connected to carbons 1,4, and 7 of a cyclononatriene ring, forming three fused pentagonal cycles. The compound may possess ...

, (cyclic) **

oxatriquinane Oxatriquinane (oxoniaperhydrotriquinacene) is an alkyl oxonium ion with formula (CH2CH2CH)3O+. It has a cyclononane backbone, with a trivalent oxygen connected to carbon 1, 4, and 7, forming three fused pentagonal rings. In contrast to most trial ...

, (cyclic) *secondary sulfonium cations, R₂SH⁺ (protonated

sulfide Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to chemical compounds l ...

s) ** dimethylsulfonium, (CH₃)₂SH⁺ (protonated dimethyl sulfide) *tertiary sulfonium cations, R₃S⁺ ** trimethylsulfonium, (CH₃)₃S⁺ *secondary fluoronium cations, R₂F⁺ ** dichlorofluoronium, Cl₂F⁺

Onium cations with polyvalent substitutions

*secondary ammonium cations having one double-bonded substitution, **diazenium, (protonated diazene) ** guanidinium, (protonated guanidine) (has a

resonance Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied periodic force (or a Fourier component of it) is equal or close to a natural frequency of the system on which it acts. When an oscillat ...

structure) *tertiary ammonium cations having one triple-bonded substitution, R≡NH+ ** nitrilium, RC≡NH⁺ (protonated nitrile) ** diazonium, N≡NH⁺ (protonated

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seve ...

) *tertiary ammonium cations having two partially double-bonded substitutions, RNH⁺R **

pyridinium Pyridinium refers to the cation . It is the conjugate acid of pyridine. Many related cations are known involving substituted pyridines, e.g. picolines, lutidines, collidines. They are prepared by treating pyridine with acids. As pyridine is oft ...

, C₅H₅NH⁺ (protonated

pyridine Pyridine is a basic (chemistry), basic heterocyclic compound, heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom. It is a highly flammable, weakl ...

) *quaternary ammonium cations having one double-bonded substitution and two single-bonded substitutions, ** iminium, (substituted protonated imine) **diazenium, (substituted protonated diazene) **thiazolium, (substituted protonated

thiazole Thiazole, or 1,3-thiazole, is a heterocyclic compound that contains both sulfur and nitrogen. The term 'thiazole' also refers to a large family of derivatives. Thiazole itself is a pale yellow liquid with a pyridine-like odor and the molecular fo ...

) *quaternary ammonium cations having two double-bonded substitutions, R=N=R⁺ **

nitronium The nitronium ion, , is a cation. It is an onium ion because its nitrogen atom has +1 charge, similar to ammonium ion . It is created by the removal of an electron from the paramagnetic nitrogen dioxide molecule , or the protonation of nitric aci ...

, **

bis(triphenylphosphine)iminium Bis(triphenylphosphine)iminium chloride is the chemical compound with the formula , often abbreviated , where Ph is phenyl , or even abbreviated PNl or NPl or PPNCl or PNPCl, where PPN or PNP stands for . This colorless salt is a source of the c ...

, ((C₆H₅)₃P)₂N⁺ *quaternary ammonium cations having one triple-bonded substitution and one single-bonded substitution, R≡NR⁺ ** diazonium, N≡NR⁺ (substituted protonated nitrogen) **nitrilium, RC≡NR⁺ (substituted protonated nitrile) *tertiary oxonium cations having one triple-bonded substitution, R≡O⁺ ** acylium ions, R−C≡O⁺ ↔ R−C⁺=O ** nitrosonium, N≡O⁺ *tertiary oxonium cations having two partially double-bonded substitutions, RO⁺R ** pyrylium, C₅H₅O⁺ *tertiary sulfonium cations having one triple-bonded substitution, R≡S⁺ ** thionitrosyl, N≡S⁺

Double onium dications

* hydrazinediium or hydrazinium(2+) dication, ⁺H₃NNH (doubly protonated hydrazine) * diazenediium cation, ⁺H₂N=NH (doubly protonated diazene) * diazynediium cation, ⁺HN≡NH⁺ (doubly protonated iitrogen)

Enium cations

The extra bond is added to a less-common parent hydride, a carbene analog, typically named ''-ene'' or ''-ylene'', which is neutral with 2 fewer bonds than the more-common hydride, typically named ''-ane'' or ''-ine''. * borenium cations, (protonated borylenes a.k.a. boranylidenes) * carbenium cations, (protonated carbenes) have a trivalent carbon atom with a +1 charge. **alkenium cations, (''n'' ≥ 2) (protonated

alkene In organic chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond. Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.H. Stephen Stoker (2015): General, Organic, an ...

s) *** methenium cation, (protonated methylene) *** ethenium, (protonated ethene) **

benzenium An arenium ion in organic chemistry is a cyclohexadienyl cation that appears as a reactive intermediate in electrophilic aromatic substitution. For historic reasons this complex is also called a Wheland intermediate, after American chemist George ...

, (protonated

benzene Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen ato ...

) ** tropylium, * silylium cations, (protonated

silylene Silylene is a chemical compound with the formula SiH2. It is the silicon analog of methylene, the simplest carbene. Silylene is a stable molecule as a gas but rapidly reacts in a bimolecular manner when condensed. Unlike carbenes, which can exis ...

s) *

nitrenium A nitrenium ion (also called: aminylium ion or imidonium ion (obsolete)) in organic chemistry is a reactive intermediate based on nitrogen with both an electron lone pair and a positive charge and with two substituents (). Nitrenium ions are i ...

cations, (protonated nitrenes) * phosphinidenium cations, (protonated phosphinidene) * mercurinium cations, (protonated organomercury compounds; formed as intermediates in oxymercuration reactions)

Substituted eniums

*diphenylcarbenium, (di-substituted methenium) * triphenylcarbenium, (tri-substituted methenium)

Ynium cations

* carbynium ions (protonated carbynes) have a divalent carbon atom with a +1 charge. **alkynium cations, (''n'' ≥ 2) (protonated

alkyne \ce \ce Acetylene \ce \ce \ce Propyne \ce \ce \ce \ce 1-Butyne In organic chemistry, an alkyne is an unsaturated hydrocarbon containing at least one carbon—carbon triple bond. The simplest acyclic alkynes with only one triple bond and no ...

s) *** methynium cation, (protonated methylidyne radical) *** ethynium, (protonated

ethyne Acetylene ( systematic name: ethyne) is the chemical compound with the formula and structure . It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in its pure ...

)

References

External links

Ions and Radicals
Queen Mary University of London * {{Authority control Cations Chemical nomenclature