Hypofluorous acid,
chemical formula
In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...
H O F, is the only known
oxyacid
An oxyacid, oxoacid, or ternary acid is an acid that contains oxygen. Specifically, it is a compound that contains hydrogen, oxygen, and at least one other element, with at least one hydrogen atom bonded to oxygen that can dissociate to produce ...
of fluorine and the only known oxoacid in which the main atom gains electrons from
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 wel ...
to create a negative oxidation state. The oxidation state of the oxygen in hypofluorites is 0. It is also the only
hypohalous acid that can be isolated as a
solid
Solid is one of the State of matter#Four fundamental states, four fundamental states of matter (the others being liquid, gas, and Plasma (physics), plasma). The molecules in a solid are closely packed together and contain the least amount o ...
. HOF is an
intermediate in the
oxidation
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a d ...
of
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 a ...
by
fluorine
Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists at standard conditions as a highly toxic, pale yellow diatomic gas. As the most electronegative reactive element, it is extremely reacti ...
, which produces
hydrogen fluoride
Hydrogen fluoride (fluorane) is an inorganic compound with the chemical formula . This colorless gas or liquid is the principal industrial source of fluorine, often as an aqueous solution called hydrofluoric acid. It is an important feedstock i ...
,
oxygen difluoride
Oxygen difluoride is a chemical compound with the formula . As predicted by VSEPR theory, the molecule adopts a "bent" molecular geometry. It is strong oxidizer and has attracted attention in rocketry for this reason. With a boiling point of -144.7 ...
,
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%†...
,
ozone
Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the lo ...
and
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 wel ...
. HOF is explosive at room temperature, forming HF and O
2:
:2 HOF → 2 HF + O
2
It was isolated in the pure form by passing F
2
gas over ice at −40 °C, collecting the HOF gas, and condensing it:
:F
2 + H
2O → HOF + HF
The compound has been characterized in the solid phase by
X-ray crystallography
X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ...
as a
bent molecule with an angle of 101°. The O–F and O–H bond lengths are 144.2 and 96.4
picometre
The picometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: pm) or picometer (American spelling) is a unit of length in the International System of Units (SI), equal to , or one trillionth of ...
s, respectively. The solid framework consists of chains with O–H···O linkages. The structure has also been analyzed in the gas phase, a state in which the H–O–F bond angle is slightly narrower (97.2°).
Among workers in
thiophene
Thiophene is a heterocyclic compound with the formula C4H4S. Consisting of a planar five-membered ring, it is aromatic as indicated by its extensive substitution reactions. It is a colorless liquid with a benzene-like odor. In most of its reacti ...
chemistry, a solution of hypofluorous acid in
acetonitrile
Acetonitrile, often abbreviated MeCN (methyl cyanide), is the chemical compound with the formula and structure . This colourless liquid is the simplest organic nitrile (hydrogen cyanide is a simpler nitrile, but the cyanide anion is not clas ...
(generated ''in situ'' by passing gaseous
fluorine
Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists at standard conditions as a highly toxic, pale yellow diatomic gas. As the most electronegative reactive element, it is extremely reacti ...
through acetonitrile that has water in it) is commonly known as Rozen's reagent.
[For Rozen's original popularizations, see:
*
*
For subsequent use, see, e.g.
*
*
]
Hypofluorites
Hypofluorites are formally derivatives of OF
−, which is the
conjugate base
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 hypofluorous acid. One example is
trifluoromethyl hypofluorite
Trifluoromethyl hypofluorite is an organofluorine compound with the formula . It exists as a colorless gas at room temperature and is highly toxic. It is a rare example of a hypofluorite (compound with an O−F bond). It is prepared by the re ...
(CF
3OF).
See also
*
Hypochlorous acid
Hypochlorous acid (HClO, HOCl, or ClHO) is a weak acid that forms when chlorine dissolves in water, and itself partially dissociates, forming hypochlorite, ClO−. HClO and ClO− are oxidizers, and the primary disinfection agents of chlorine so ...
, a related compound that is more technologically important but has not been obtained in pure form.
References
{{Hydrogen compounds
Halogen oxoacids
Hydrogen compounds
Hypofluorites
Mineral acids