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| Names | |
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| IUPAC name Oxygen difluoride | |
Other names
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| Identifiers | |
3D model (JSmol) | |
| ChEBI | |
| ChemSpider |
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| ECHA InfoCard | 100.029.087 |
| EC Number |
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| RTECS number |
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| UNII | |
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| Properties | |
| OF2 | |
| Molar mass | 53.9962 g/mol |
| Appearance | colorless gas, pale yellow liquid when condensed |
| Odor | peculiar, foul |
| Density |
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| Melting point | −223.8 °C (−370.8 °F; 49.3 K) |
| Boiling point | −144.75 °C (−228.55 °F; 128.40 K) |
| hydrolyzes[1] slowly | |
| Vapor pressure | 48.9 atm (at −58.0 °C or −72.4 °F or 215.2 K[a]) |
| Structure | |
| C2V | |
| Thermochemistry | |
| 43.3 J/mol K | |
Std molar entropy(S⦵298) | 247.46 J/mol K |
Std enthalpy of formation(ΔfH⦵298) | 24.5 kJ mol−1 |
Gibbs free energy(ΔfG⦵) | 41.8 kJ/mol |
| Hazards | |
| GHS labelling:[4] | |
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| Danger | |
| H270,H314,H330 | |
| NFPA 704 (fire diamond) | |
| Lethal dose or concentration (LD, LC): | |
LC50 (median concentration) |
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| NIOSH (US health exposure limits): | |
PEL (Permissible) | TWA 0.05 ppm (0.1 mg/m3)[2] |
REL (Recommended) | C 0.05 ppm (0.1 mg/m3)[2] |
IDLH (Immediate danger) | 0.5 ppm[2] |
| Related compounds | |
Related compounds | |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Oxygen difluoride is achemical compound with theformulaOF2. As predicted byVSEPR theory, the molecule adopts a bentmolecular geometry.[citation needed] It is a strongoxidizer and has attracted attention in rocketry for this reason.[5] With aboiling point of −144.75 °C, OF2 is the most volatile (isolable) triatomic compound.[6] The compound is one of many knownoxygen fluorides.
Oxygen difluoride was first reported in 1929; it was obtained by the electrolysis of moltenpotassium fluoride andhydrofluoric acid containing small quantities ofwater.[7][8] The modern preparation entails the reaction offluorine with a dilute aqueous solution ofsodium hydroxide, withsodium fluoride as a side-product:
It is a covalently bonded molecule with abent molecular geometry and a F-O-F bond angle of 103 degrees. Its powerful oxidizing properties are suggested by theoxidation number of +2 for theoxygen atom instead of its normal −2.
Above 200 °C,OF2 decomposes to oxygen and fluorine by aradical mechanism.
OF2 reacts with many metals to yieldoxides andfluorides.Nonmetals also react:phosphorus reacts withOF2 to formPF5 andPOF3;sulfur givesSO2 andSF4; and unusually for anoble gas,xenon reacts (at elevated temperatures) yieldingXeF4 and xenon oxyfluorides.
Reactions of oxygen difluoride and hydrogen halides or halide salts produce the free halogen. For example:
4 HCl + OF2 → 2 HF + H2O + 2 Cl2
Oxygen difluoride reacts with water to formhydrofluoric acid:
It can oxidizesulfur dioxide tosulfur trioxide and elementalfluorine:
However, in the presence ofUV radiation, the products aresulfuryl fluoride (SO2F2) andpyrosulfuryl fluoride (S2O5F2):
![[icon]](/mt/?noimg=&dark=on&url=http%3a%2f%2fen.wikipedia.org%2fwiki%2fFile%3aWiki_letter_w_cropped.svg) | This sectionneeds expansion. You can help byadding missing information.(August 2018) |
Oxygen difluoride is considered an unsafe gas due to its oxidizing properties. It reacts explosively with water,hydrogen sulfide,diborane, andnitrogen oxides.[9] Hydrofluoric acid produced by the hydrolysis ofOF2 with water is highly corrosive and toxic, capable of causingnecrosis, leaching calcium from the bones and causing cardiovascular damage, among a host of other highly toxic effects. Other acute poisoning effects include:pulmonary edema, bleeding lungs, headaches, etc.[10] Chronic exposure to oxygen difluoride, like that of other chemicals that release fluoride ions, can lead tofluorosis and other symptoms of chronicfluoride poisoning. Oxygen difluoride may be associated with kidney damage.[10] The maximum workplace exposure limit is 0.05 ppm.[11][10]
InRobert L. Forward'sscience fiction novelCamelot 30K, oxygen difluoride was used as a biochemical solvent by fictional life forms living in the solar system'sKuiper belt. WhileOF2 would be a solid at 30 K, the fictional alien lifeforms were described asendothermic, maintaining elevated body temperatures and liquidOF2 blood byradiothermal heating.
