Chloryl
Encyclopedia
In chemistry
, chloryl refers to the red-colored cation having the chemical formula
. It is polyatomic
ion, structurally identical to chlorite
and having the same chemical formula but with chlorine in the +5 oxidation state
rather than +3. In chloryl, the two oxygen atoms oxidize the central chlorine atom, forming one double covalent bond each, and another elmement or ion oxidizes the chlorine further, leaving the chlorine with one electron pair. (In chlorite, one oxygen atom forms a double covalent bond with the central chlorine atom, and another oxygen atom forms a single bond with the chlorine atom and an ionic bond, or, more rarely, another single covalent bond). Chloryl is isoelectronic with sulfur dioxide
.. Chloryl compounds, such as and [ClO2][RuF6] are all highly reactive, and react violently with water and most organic compounds.
character.
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.
. 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 cloryl cation.
The second category features red-colored compounds that are highly reactive. These include chloryl fluorosulfate, , 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
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
s rather than true salts.
One notable chloryl compound is dichlorine hexoxide
, 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
. For example:
Other synthesis routes are also possible, including:
Metathesis reactions may be carried out with strong Lewis bases. For example, the reaction of the hexafluoroplatinate salt with nitryl fluoride
yields the nitronium salt:
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
, chloryl refers to the red-colored cation having the chemical formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
. It is polyatomic
Polyatomic ion
A polyatomic ion, also known as a molecular ion, is a charged species composed of two or more atoms covalently bonded or of a metal complex that can be considered as acting as a single unit in the context of acid and base chemistry or in the formation of salts. The prefix "poly-" means "many," in...
ion, structurally identical to chlorite
Chlorite
The chlorite ion is ClO2−. A chlorite is a compound that contains this group,with chlorine in oxidation state +3. Chlorites are also known as salts of chlorous acid.-Oxidation states:...
and having the same chemical formula but with chlorine in the +5 oxidation state
Oxidation state
In chemistry, the oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. The formal oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic. Oxidation states are typically represented by...
rather than +3. In chloryl, the two oxygen atoms oxidize the central chlorine atom, forming one double covalent bond each, and another elmement or ion oxidizes the chlorine further, leaving the chlorine with one electron pair. (In chlorite, one oxygen atom forms a double covalent bond with the central chlorine atom, and another oxygen atom forms a single bond with the chlorine atom and an ionic bond, or, more rarely, another single covalent bond). Chloryl is isoelectronic with sulfur dioxide
Sulfur dioxide
Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...
.. Chloryl compounds, such as and [ClO2][RuF6] are all highly reactive, and react violently with water and most organic compounds.
Structure
The cation is isoelectronic with , and has a bent structure with a bond angle close to 120°. The bond-stretching force constant for its bonds indicate that the Cl–O bond has double bondDouble bond
A double bond in chemistry is a chemical bond between two chemical elements involving four bonding electrons instead of the usual two. The most common double bond, that between two carbon atoms, can be found in alkenes. Many types of double bonds between two different elements exist, for example in...
character.
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 fluorideChloryl fluoride
Chloryl fluoride is the chemical compound with the formula ClO2F. It is commonly encountered side-product in reactions of chlorine fluorides with oxygen sources. It is the acyl fluoride of chloric acid.-Preparation:...
. 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 cloryl cation.
The second category features red-colored compounds that are highly reactive. These include chloryl fluorosulfate, , and dichloryl trisulfate, . These chloryl compounds form red solutions in fluorosulfuric acid
Fluorosulfuric acid
Fluorosulfuric acid is the inorganic compound with the formula HSO3F. It is one of the strongest acids commercially available and is a superacid. The formula HFSO3 emphasizes its relationship to sulfuric acid, H2SO4; HSO3F is a tetrahedral molecule.-Chemical properties:Fluorosulfuric acid is a...
, and do contain a red-colored cation which dissociates in solution. In the solid state, the Raman
Raman spectroscopy
Raman spectroscopy is a spectroscopic technique used to study vibrational, rotational, and other low-frequency modes in a system.It relies on inelastic scattering, or Raman scattering, of monochromatic light, usually from a laser in the visible, near infrared, or near ultraviolet range...
and infrared
Infrared spectroscopy
Infrared spectroscopy is the spectroscopy that deals with the infrared region of the electromagnetic spectrum, that is light with a longer wavelength and lower frequency than visible light. It covers a range of techniques, mostly based on absorption spectroscopy. As with all spectroscopic...
spectra indicate strong interactions with the counterion. Not all chloryl compounds in the solid state are necessarily ionic. The reaction products of with
Boron trifluoride
Boron trifluoride is the chemical compound with the formula BF3. This pungent colourless toxic gas forms white fumes in moist air. It is a useful Lewis acid and a versatile building block for other boron compounds.-Structure and bonding:...
and
Phosphorus pentafluoride
Phosphorus pentafluoride, PF5, is a phosphorus halide. It's a colourless gas at room temperature and pressure.-Structure:Single-crystal X-ray studies indicate PF5 molecule has two distinct P−F bonds : P−Fax = 158.0 pm and P−Feq = 152.2 pm...
are assumed to be molecular adduct
Adduct
An adduct is a product of a direct addition of two or more distinct molecules, resulting in a single reaction product containing all atoms of all components. The resultant is considered a distinct molecular species...
s rather than true salts.
One notable chloryl compound is dichlorine hexoxide
Dichlorine hexoxide
Dichlorine hexoxide is the chemical compound with the formula . This chlorine oxide is the mixed anhydride of chloric and perchloric acids. It is produced by reaction between chlorine dioxide and excess ozone:...
, 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
Lewis acid
]The term Lewis acid refers to a definition of acid published by Gilbert N. Lewis in 1923, specifically: An acid substance is one which can employ a lone pair from another molecule in completing the stable group of one of its own atoms. Thus, H+ is a Lewis acid, since it can accept a lone pair,...
. For example:
- + → [ClO2][AsF6]
Other synthesis routes are also possible, including:
- 5 + 3 → 2 [ClO2][AsF6] + + 4
- + 2 → [ClO2][SbF6] + +
Metathesis reactions may be carried out with strong Lewis bases. For example, the reaction of the hexafluoroplatinate salt with nitryl fluoride
Nitryl fluoride
Nitryl fluoride, NO2F, is a colourless gas and strong oxidizing agent, which is used as an oxidizer in rocket propellants and as a fluorinating agent. It is a molecular species, not ionic, consistent with its low boiling point...
yields the nitronium salt:
- [ClO2][PtF6] + → [NO2][PtF6] +