In
chemistry
Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds made of atoms, molecules and ions ...
, chloryl refers to a triatomic
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 convent ...
with
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, ...
. This species has the same general structure as
chlorite
The chlorite ion, or chlorine dioxide anion, is the halite with the chemical formula of . A chlorite (compound) is a compound that contains this group, with chlorine in the oxidation state of +3. Chlorites are also known as salts of chlorous ac ...
() but it is electronically different, with chlorine having a +5
oxidation state
In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...
(rather than the +3 of
chlorite
The chlorite ion, or chlorine dioxide anion, is the halite with the chemical formula of . A chlorite (compound) is a compound that contains this group, with chlorine in the oxidation state of +3. Chlorites are also known as salts of chlorous ac ...
). This makes it a rare example of a positively charged oxychloride. Chloryl compounds, such as
and
2">lO2RuF
6], are all highly reactive and react violently with water and most organic compounds.
Structure
The cation is
isoelectronic
Isoelectronicity is a phenomenon observed when two or more molecules have the same structure (positions and connectivities among atoms) and the same electronic configurations, but differ by what specific elements are at certain locations in the ...
with ,
and has a bent structure with a bond angle close to 120°. The Cl–O bond is of
bond order
In chemistry, bond order, as introduced by Linus Pauling, is defined as the difference between the number of bonds and anti-bonds.
The bond order itself is the number of electron pairs (covalent bonds) between two atoms. For example, in diat ...
1.5, with its Lewis structure consisting of a
double bond
In chemistry, a double bond is a covalent bond between two atoms involving four bonding electrons as opposed to two in a single bond. Double bonds occur most commonly between two carbon atoms, for example in alkenes. Many double bonds exist betw ...
and a
dative bond
In coordination chemistry, a coordinate covalent bond, also known as a dative bond, dipolar bond, or coordinate bond is a kind of two-center, two-electron covalent bond in which the two electrons derive from the same atom. The bonding of metal ...
which does not utilize d-orbitals.
The red color of is caused by electron transitions into an antibonding orbital. The analogous transition in is not in the visible spectrum, so is colorless. The strength of interaction with the counterion affects the energy of this antibonding orbital; thus, in colorless chloryl compounds, strong interactions with the counterion, corresponding with the higher covalent character of the bonding, shift the transition energy out of the visible spectrum.
Compounds
There are two categories of chloryl compounds. The first category is colorless, and includes
chloryl fluoride
Chloryl fluoride is the chemical compound with the formula ClO2F. It is commonly encountered as side-product in reactions of chlorine fluorides with oxygen sources. It is the acyl fluoride of chloric acid.
Preparation
ClO2F was first reported by ...
(). These are moderately reactive. Although named as an ionic "chloryl" compound, chloryl fluoride is more a covalent compound than an ionic compound of fluoride and chloryl cation.
The second category features red-colored compounds that are highly reactive. These include
chloryl fluorosulfate
In chemistry, chloryl refers to a triatomic cation with chemical formula . This species has the same general structure as chlorite () but it is electronically different, with chlorine having a +5 oxidation state (rather than the +3 of chlorite). ...
, , and dichloryl trisulfate, . These chloryl compounds form red solutions in
fluorosulfuric acid, and do contain a red-colored cation which dissociates in solution. In the solid state, the
Raman and
infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
spectra indicate strong interactions with the counterion.
Not all chloryl compounds in the solid state are necessarily ionic. The reaction products of with
and
are assumed to be molecular
adduct
An adduct (from the Latin ''adductus'', "drawn toward" alternatively, a contraction of "addition product") is a product of a direct addition of two or more distinct molecules, resulting in a single reaction product containing all atoms of all co ...
s rather than true
salts
In chemistry, a salt is a chemical compound consisting of an ionic assembly of positively charged cations and negatively charged anions, which results in a compound with no net electric charge. A common example is table salt, with positively cha ...
.
One notable chloryl compound is
dichlorine hexoxide
Dichlorine hexoxide is the chemical compound with the molecular formula , which is correct for its gaseous state. However, in liquid or solid form, this chlorine oxide ionizes into the dark red ionic compound chloryl perchlorate , which may be tho ...
, which exists as an ionic compound more accurately described as ''chloryl perchlorate'', .
It is a red fuming liquid under standard conditions.
Chloryl compounds are best prepared by the reaction of with a strong
Lewis acid
A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any sp ...
. For example:
: + →
2">lO2AsF
6]
Other synthesis routes are also possible, including:
:5 + 3 → 2
2">lO2AsF
6] + + 4
: + 2 →
2">lO2SbF
6] + +
Salt metathesis reaction, Metathesis reactions may be carried out with strong
Lewis bases. For example, the reaction of the hexafluoroplatinate salt with
nitryl fluoride
Nitryl fluoride, NO2F, is a colourless gas and strong oxidizing agent, which is used as a fluorinating agent and has been proposed as an oxidiser in rocket propellants (though never flown).
It is a molecular species, not ionic, consistent with it ...
yields the
nitronium salt:
:
2">lO2PtF
6] + →
2">O2PtF
6] +
References
External links
*{{Commonscatinline, Chloryl cation
Chloryl compounds,
Cations
Oxycations
Chlorine oxides