Oxygen difluoride

Oxygen difluoride
Names
	Other names oxygen fluoride; hypofluorous anhydride
Identifiers
CAS Number	7783-41-7 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:30494 ;
ChemSpider	22953 ;
ECHA InfoCard	100.029.087
EC Number	231-996-7;
PubChem CID	24547;
RTECS number	RS2100000;
CompTox Dashboard (EPA)	DTXSID20894009 ;
	InChI InChI=1S/F2O/c1-3-2 Key: UJMWVICAENGCRF-UHFFFAOYSA-N ; InChI=1/F2O/c1-3-2 Key: UJMWVICAENGCRF-UHFFFAOYAI;
	SMILES FOF;
Properties
Chemical formula	OF2
Molar mass	53.9962 g/mol
Appearance	colorless gas, pale yellow liquid when condensed
Odor	peculiar, foul
Density	1.90 g/cm3 (-224° C, liquid),; 1.719 g/cm3 (-183° C, liquid), 1.521 g/cm3 (liquid at −145 °C), 1.88 g/l (gas at room temperature)
Melting point	−223.8 °C (−370.8 °F; 49.3 K)
Boiling point	−144.75 °C (−228.55 °F; 128.40 K)
Solubility in water	hydrolyzes
Vapor pressure	48.9 atm (at −58.0 °C or −72.4 °F or 215.2 K)
Thermochemistry
Heat capacity (C)	43.3 J/mol K
Std molar; entropy (S⦵298)	246.98 J/mol K
Std enthalpy of; formation (ΔfH⦵298)	24.5 kJ mol−1
Gibbs free energy (ΔfG⦵)	42.5 kJ/mol
Hazards
NFPA 704 (fire diamond)	4 0 3 OX
	Lethal dose or concentration (LD, LC):
LC50 (median concentration)	2.6 ppm (rat, 1 hr); 1.5 ppm (mouse, 1 hr); 26 ppm (dog, 1 hr); 16 ppm (monkey, 1 hr)
	NIOSH (US health exposure limits):
PEL (Permissible)	TWA 0.05 ppm (0.1 mg/m3)
REL (Recommended)	C 0.05 ppm (0.1 mg/m3)
IDLH (Immediate danger)	0.5 ppm
Related compounds
Related compounds	HFO; O2F2; NHF2; NF3; SCl2
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Oxygen difluoride is the chemical compound with the formula OF₂. As predicted by VSEPR theory, the molecule adopts a "bent" molecular geometry similar to that of water, but it has very different properties, being a strong oxidizer.

Preparation

Oxygen difluoride was first reported in 1929; it was obtained by the electrolysis of molten potassium fluoride and hydrofluoric acid containing small quantities of water.^[4]^[5] The modern preparation entails the reaction of fluorine with a dilute aqueous solution of sodium hydroxide, with sodium fluoride as a side-product:

2 F₂ + 2 NaOH → OF₂ + 2 NaF + H₂O

Reactions

Its powerful oxidizing properties are suggested by the oxidation number of +2 for the oxygen atom instead of its normal −2. Above 200 °C, OF₂ decomposes to oxygen and fluorine via a radical mechanism.

OF₂ reacts with many metals to yield oxides and fluorides. Nonmetals also react: phosphorus reacts with OF₂ to form PF₅ and POF₃; sulfur gives SO₂ and SF₄; and unusually for a noble gas, xenon reacts, at elevated temperatures, yielding XeF₄ and xenon oxyfluorides.

Oxygen difluoride reacts very slowly with water to form hydrofluoric acid:

OF₂ (aq) + H₂O (l) → 2 HF (aq) + O₂ (g)

OF₂ + SO₂ → SO₃ + F₂

However, in the presence of UV radiation the products are sulfuryl fluoride, SO
₂F
₂, and pyrosulfuryl fluoride, S
₂O
₅F
₂:

OF₂ + 2 SO₂ → S
₂O
₅F
₂

Safety

Oxygen diflouride is considered an unsafe gas due to its oxidizing properties.

Popular culture

In Robert L. Forward's science fiction novel Camelot 30K, oxygen difluoride was used as a biochemical solvent by fictional life forms living in the solar system's Kuiper belt. While OF
₂ would be a solid at 30 K, the fictional alien lifeforms were described as endothermic, maintaining elevated body temperatures and liquid OF
₂ blood by radiothermal heating.

Notes

^ This is its critical temperature, which is below ordinary room temperature

References

^ "difluorine monoxide;oxygen difluoride,physical properties,suppliers,CAS,MSDS,structure,Molecular Formula, Molecular Weight ,Solubility,boiling point, melting point". www.chemyq.com.
^ ^a ^b ^c NIOSH Pocket Guide to Chemical Hazards. "#0475". National Institute for Occupational Safety and Health (NIOSH).
^ "Oxygen difluoride". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
^ Lebeau, P.; Damiens, A. (1929). "Sur un nouveau mode de préparation du fluorure d'oxygène" [A new method of preparation of oxygen fluoride]. Comptes rendus hebdomadaires des séances de l'Académie des Sciences (in French). 188: 1253–1255. Retrieved February 21, 2013. {{cite journal}}: Cite has empty unknown parameter: |month= (help)
^ Lebeau, P.; Damiens, A. (1927). "Sur l'existence d'un composé oxygéné du fluor" [The existence of an oxygen compound of fluorine]. Comptes rendus hebdomadaires des séances de l'Académie des Sciences (in French). 185: 652–654. Retrieved February 21, 2013. {{cite journal}}: Cite has empty unknown parameter: |month= (help)

External links

[2] This is its critical temperature, which is below ordinary room temperature

[1] "difluorine monoxide;oxygen difluoride,physical properties,suppliers,CAS,MSDS,structure,Molecular Formula, Molecular Weight ,Solubility,boiling point, melting point". www.chemyq.com.

[PGCH-3] NIOSH Pocket Guide to Chemical Hazards. "#0475". National Institute for Occupational Safety and Health (NIOSH).

[4] "Oxygen difluoride". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).

[5] Lebeau, P.; Damiens, A. (1929). "Sur un nouveau mode de préparation du fluorure d'oxygène" [A new method of preparation of oxygen fluoride]. Comptes rendus hebdomadaires des séances de l'Académie des Sciences (in French). 188: 1253–1255. Retrieved February 21, 2013. {{cite journal}}: Cite has empty unknown parameter: |month= (help)

[6] Lebeau, P.; Damiens, A. (1927). "Sur l'existence d'un composé oxygéné du fluor" [The existence of an oxygen compound of fluorine]. Comptes rendus hebdomadaires des séances de l'Académie des Sciences (in French). 185: 652–654. Retrieved February 21, 2013. {{cite journal}}: Cite has empty unknown parameter: |month= (help)

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