Perchloryl fluoride

Perchloryl fluoride

Perchloryl fluoride 100px
Names
IUPAC name Perchloryl fluoride
Other names Chlorine oxyfluoride, Perchlorofluoride, Chlorine fluorine oxide, Trioxychlorofluoride, Perchloric acid fluoride
Identifiers
CAS Number	7616-94-6 N
ChemSpider	22680 Y
EC Number	231-526-0
Jmol 3D model	Interactive image
PubChem	24258
RTECS number	SD1925000
InChI InChI=1S/ClFO3/c2-1(3,4)5 Y Key: XHFXMNZYIKFCPN-UHFFFAOYSA-N Y InChI=1/ClFO3/c2-1(3,4)5 Key: XHFXMNZYIKFCPN-UHFFFAOYAO
SMILES FCl(=O)(=O)=O
Properties
Chemical formula	ClO3F
Molar mass	102.4496 g/mol
Appearance	Colorless gas
Odor	sweet odor
Density	1.434 g/cm3
Melting point	−147.8 °C (−234.0 °F; 125.3 K)
Boiling point	−46.7 °C (−52.1 °F; 226.5 K)
Solubility in water	0.06 g/100 ml (20 °C)
Vapor pressure	10.5 atm (20°C)
Viscosity	3.91 x 10−3 Pa.s (@ melting point)
Structure
Molecular shape	Tetrahedral
Thermochemistry
Std enthalpy of formation (ΔfHo298)	−5.7
Vapor pressure	{{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Perchloryl fluoride is a reactive gas with the chemical formula ClO
₃F. It has a characteristic sweet odor that resembles gasoline and kerosene. It is toxic and is a powerful oxidizing and fluorinating agent. It is the acid fluoride of perchloric acid.

In spite of its small enthalpy of formation (ΔH_f^O = −5.7), it is stable, decomposing only at 400 °C. It is quite reactive towards reducing agents and anions, however, with the chlorine atom acting as an electrophile. It reacts explosively with reducing agents such as amides, metals, hydrides, etc. Its hydrolysis in water occurs very slowly, unlike that of chloryl fluoride.

Synthesis and chemistry

Perchloryl fluoride is produced primarily by the fluorination of perchlorates. Antimony pentafluoride is a commonly used fluorinating agent:

ClO⁻
₄ + 3 HF + 2 SbF
₅ → ClO
₃F + H
₃O⁺
+ 2 SbF⁻
₆

ClO
₃F reacts with alcohols to produce alkyl perchlorates, which are extremely shock-sensitive explosives. Using Friedel-Crafts catalysts, it can be used for introducing the –ClO
₃ group into aromatic rings via electrophilic aromatic substitution.

Applications

Perchloryl fluoride is used in organic chemistry as a mild fluorinating agent. It was the first industrially relevant electrophilic fluorinating agent, used since the 1960s for producing fluorinated steroids.

Perchloryl fluoride was investigated as a high performance liquid rocket fuel oxidizer. In comparison with chlorine pentafluoride and bromine pentafluoride, it has significantly lower specific impulse, but does not tend to corrode tanks. It does not require cryogenic storage.

It can also be used in flame photometry as an excitation source.

Safety

Perchloryl fluoride is toxic, with a TLV of 3 ppm. It is a strong lung- and eye-irritant capable of producing burns on exposed skin. Its IDLH level is 100 ppm. Symptoms of exposure include dizziness, headaches, syncope, and cyanosis. Exposure to toxic levels causes severe respiratory tract inflammation and pulmonary edema.