Dioxidanylium, which is protonated molecular oxygen, or just protonated oxygen, is an
ion
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 conven ...
with formula .
It is formed when hydrogen containing substances
combust, and exists in the
ionosphere, and in
plasmas that contain
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as we ...
and
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 ...
.
Oxidation by O
2 in
superacids could be by way of the production of protonated molecular oxygen.
It is the
conjugate acid
A conjugate acid, within the Brønsted–Lowry acid–base theory, is a chemical compound formed when an acid donates a proton () to a base—in other words, it is a base with a hydrogen ion added to it, as in the reverse reaction it loses a ...
of
dioxygen
There are several known allotropes of oxygen. The most familiar is molecular oxygen (O2), present at significant levels in Earth's atmosphere and also known as dioxygen or triplet oxygen. Another is the highly reactive ozone (O3). Others are: ...
. The
proton affinity
The proton affinity (PA, ''E''pa) of an anion or of a neutral atom or molecule is the negative of the enthalpy change in the reaction between the chemical species concerned and a proton in the gas phase:
::: A- + H+ -> HA
::: B + H+ -> BH+
...
of dioxygen (O
2) is 4.4 eV.
Significance
Protonated molecular oxygen is of interest in trying to detect dioxygen in space. Because Earth's atmosphere is full of O
2, its spectrum from a space object is impossible to observe from the ground. However should be much more detectable.
Formation
Reaction of
dioxygenyl
The dioxygenyl ion, , is a rarely-encountered oxycation in which both oxygen atoms have a formal oxidation state of . It is formally derived from oxygen by the removal of an electron:
:O2 → + e−
The energy change for this process is ca ...
with hydrogen:
: + H
2 → + H
•
The reaction of the
trihydrogen cation
The trihydrogen cation or protonated molecular hydrogen is a cation (positive ion) with formula , consisting of three hydrogen nuclei ( protons) sharing two electrons.
The trihydrogen cation is one of the most abundant ions in the universe. I ...
with dioxygen is approximately thermoneutral:
:O
2 + → + H
2
When atomic hydrogen, created in an electric discharge is rapidly cooled with oxygen and condensed in solid neon, several reactive ions and molecules are produced. These include HO
2 (
hydroperoxyl
The hydroperoxyl radical
Radical may refer to:
Politics and ideology Politics
*Radical politics, the political intent of fundamental societal change
*Radicalism (historical), the Radical Movement that began in late 18th century Britain and sprea ...
), HOHOH
−, H
2O(HO), HOHO
− as well as . This reaction also forms
hydrogen peroxide
Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3% ...
(H
2O
2) and
hydrogen tetroxide
Hydrogen polyoxides (also known as oxidanes, oxohydrogens, or oxyhydrogens) are chemical compounds that consist only of hydrogen and oxygen atoms, are bonded exclusively by single bonds (i.e., they are saturated), and are acyclic (have molecular ...
(H
2O
4).
Properties
In the infrared spectrum the ''v''
1 band due to vibrating O–H has a
band head In spectroscopy a band head is the abrupt edge of a spectroscopic band
Spectral bands are parts of the electromagnetic spectrum of specific wavelengths, which can be filtered by a standard filter. In nuclear physics, spectral bands are referred to ...
at 3016.73 cm
−1.
Reactions
A helium complex (He–O
2H
+) also is known.
[
appears to react rapidly with hydrogen:][
: + H2O → O2 + H3O+
]
Related
The protonated molecular oxygen dimer has a lower energy than that of protonated molecular oxygen.
References
{{Reflist
Reactive oxygen species
Cations
Hydrogen compounds