Wiki: Onium ion - upcScavenger

In chemistry, an onium ion is a cation formally obtained by the protonation of mononuclear parent hydride of a pnictogen (group 15 of the periodic table), chalcogen (group 16), or halogen (group 17). The oldest-known onium ion, and the namesake for the class, is ammonium, , the protonated derivative of ammonia, .

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 groups, 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 are known as onium compounds or onium salts.

Onium ions and onium compounds are inversely analogous to ions and :

Lewis bases form onium ions when the central atom gains one more bond and becomes a positive cation.
Lewis acids form ions when the central atom gains one more bond and becomes a negative anion. Advanced Organic Chemistry: Reactions and mechanisms, Maya Shankar Singh, 2007, Dorling Kindersley,

Simple onium cations (hydrides with no substitutions)

boron">

[[Group 13|Boron group (boron group) onium cations

boronium cation, (protonated borane)

further boronium cations, (protonated boranes)

carbo">

[[Group 14|Carbon group (carbon group) onium cations

(protonated ) have a pentacoordinated carbon atom with a +1 charge.

alkanium cations, (protonated )

methanium, (protonated methane) (Sometimes called carbonium ion, because it is the simplest member of that class, but that use is deprecated because of multiple definitions. Carbonium ion, IUPAC Gold Book Sometimes called methonium, but methonium also has multiple definitions. Abundant in outer space.)
ethanium, (protonated ethane)
propanium, (propane 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 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) (should not be called siliconium RC-82. Cations, Queen Mary University of London))

disilanium, (protonated disilane)
further silanium cations, (protonated silanes)

germonium, (protonated germane)
stannonium, (protonated stannylene, ) (not protonated stannane )
plumbonium, (protonated plumbylene, ) (not protonated plumbane )
flerovonium, (protonated flerovylene, ) (not protonated flerovium )

pnict">

[[Group 15|Pnictogen (pnictogen) onium cations

ammonium (IUPAC name azanium), (protonated ammonia (IUPAC name azane))
phosphonium, (protonated phosphine)
arsonium, (protonated arsine)
stibonium, (protonated stibine)
bismuthonium, (protonated bismuthine)
moscovonium, (protonated moscovium)

chalc">

[[Group 16|Chalcogen (chalcogen) onium cations

oxonium ion, (protonated water (IUPAC name oxidane). Oxonium is better known as hydronium, though hydronium implies a solvation or hydrated proton. It may also be called hydroxonium.)
sulfonium, (protonated hydrogen sulfide)
selenonium, (protonated hydrogen selenide)
telluronium, (protonated hydrogen telluride)
polononium, (protonated hydrogen polonide)
livermoronium, (protonated Livermorium)

Hydrogen onium cation

hydrogenonium, better known as trihydrogen cation, (protonated molecular or diatomic hydrogen), found in ionized hydrogen and interstellar space

halog">

[[Group 17|Halogen (halogen) onium cations, , (protonated )

fluoronium, (protonated hydrogen fluoride)
chloronium, (protonated hydrogen chloride)
bromonium, (protonated hydrogen bromide)
iodonium, (protonated hydrogen iodide)
astatonium, (protonated hydrogen astatide)
tennessonium, (protonated Tennessine)

Pseudohalogen onium cations

aminodiazonium, (protonated hydrazoic acid)
methylidyneammonium and hydrocyanonium, , isomers (protonated hydrogen cyanide)

noble">

[[Group 18|Noble gas (noble gas) onium cations

hydrohelium or helonium, better known as helium hydride ion, (protonated helium)
neonium, (protonated neon)
argonium, (protonated argon)
kryptonium ion, (protonated krypton)
xenonium, (protonated xenon)
radonium, (protonated radon)
oganessonium (protonated oganesson)

Onium cations with monovalent substitutions

primary ammonium cations, or (protonated primary )

hydroxylammonium, (protonated hydroxylamine)
methylammonium, (protonated methylamine)
ethylammonium, (protonated ethylamine)
hydrazinium, or diazanium, (protonated hydrazine, a.k.a. diazane)
anilinium (a.k.a. phenylammonium), (protonated aniline, a.k.a. phenylamine, aminobenzene)

secondary ammonium cations, (protonated secondary )

dimethylammonium (sometimes dimethylaminium), (protonated dimethylamine)
diethylammonium (sometimes diethylaminium), (protonated diethylamine)
ethylmethylammonium, (protonated ethylmethylamine)
diethanolammonium (sometimes diethanolaminium), (protonated diethanolamine)

tertiary ammonium cations, (protonated tertiary )

trimethylammonium (protonated trimethylamine)
triethylammonium (protonated triethylamine)

quaternary ammonium cations, or

tetrafluoroammonium,
tetramethylammonium,
tetraethylammonium,
tetrapropylammonium,
tetrabutylammonium, or abbreviated
trimethyl ammonium compounds,
didecyldimethylammonium,
pentamethylhydrazinium,

quaternary phosphonium cations, or

tetraphenylphosphonium,

quaternary arsonium cations, or

tetraphenylarsonium,

quaternary stibonium cations, or

tetraphenylstibonium,

primary oxonium cations, (protonated alcohols )

alkyloxonium cations (protonated alcohols)

methyloxonium, (protonated methanol)
ethyloxonium, (protonated ethanol)

dioxidanonium (hydroxylhydronium), (protonated hydrogen peroxide)

secondary oxonium cations, (protonated ethers )

dialkyloxonium cations (protonated )

dimethyloxonium, (protonated dimethyl ether)

tertiary oxonium cations,

trifluorooxonium, (hypothetical)
trimethyloxonium,
triethyloxonium,
oxatriquinacene, (cyclic oxonium ion)
oxatriquinane, (cyclic oxonium ion)

primary sulfonium cations, (protonated )
secondary sulfonium cations, (protonated )

dimethylsulfonium, (protonated dimethyl sulfide)

tertiary sulfonium cations,

trimethylsulfonium,

tertiary selenonium cations,

triphenylselenonium,

tertiary telluronium cations,

triphenyltelluronium,

primary fluoronium cations, (protonated fluorides RF)
secondary fluoronium cations,

dichlorofluoronium,

secondary iodonium cations,

diphenyliodonium,

Onium cations with polyvalent substitutions

secondary ammonium cations having one double-bonded substitution,

diazenium, (protonated diazene)
guanidinium, (protonated guanidine) (has a resonance structure and a planar molecular geometry)

tertiary ammonium cations having one triple-bonded substitution, R≡NH+

nitrilium, (protonated nitrile)
diazonium or diazynium, (protonated nitrogen, in other words, protonated diazyne)

Heterocycle tertiary ammonium cations where nitrogen is a member of a ring, (the ring may be Aromaticity)

pyridinium, (protonated pyridine)

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)

quaternary ammonium cations having two double-bonded substitutions,

nitronium ion,
bis(triphenylphosphine)iminium,

quaternary ammonium cations having one triple-bonded substitution and one single-bonded substitution,

diazonium, (substituted protonated nitrogen, in other words, substituted protonated diazyne)
nitrilium, (substituted protonated nitrile)

tertiary oxonium cations having one triple-bonded substitution,

,
nitrosonium,

cyclic tertiary oxonium cations where oxygen is a member of a ring, (the ring may be aromatic)

pyrylium salt,

tertiary sulfonium cations having one triple-bonded substitution,

thionitrosyl,

dihydroxyoxoammonium, (protonated nitric acid)
trihydroxyoxosulfonium, (protonated sulfuric acid)

Double onium dications

hydrazinediium or hydrazinium(2+) dication, (doubly protonated hydrazine, in other words, doubly protonated diazane)
diazenediium cation, (doubly protonated diazene)
diazynediium cation, (doubly protonated dinitrogen, in other words, doubly protonated diazyne)

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 ion cations, (protonated a.k.a. )
carbenium ion cations, (protonated ) have a tricoordinated carbon atom with a +1 charge.

alkenium cations, ( n ≥ 2) (protonated )

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

benzenium, (protonated benzene)
tropylium, (protonated tropylidene)

silylium ion cations, (protonated )
nitrenium ion cations, (protonated )
phosphinidenium cations, (protonated phosphinidene)
mercurinium ion cations, (protonated organomercury compounds; formed as intermediates in oxymercuration reactions)

Substituted eniums

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

Ynium cations

(protonated ) have a carbon atom with a +1 charge.

alkynium cations, ( n ≥ 2) (protonated )

methynium cation, (protonated methylidyne radical)
ethynium, (protonated ethyne)

Onium ion

( Cations )

Account

Navigation

Statistics

Onium ion ( Cations )

Account

Navigation

Statistics

Onium ion

( Cations )