Dioxygenyl

Structure and molecular properties

has a bond order of 2.5, and a bond length of 112.3 pm in solid O2[AsF6]. It is isoelectronic with nitric oxide and is paramagnetic. The bond energy is 625.1 kJ mol−1 and the stretching frequency is 1858 cm−1, both of which are high relative to most of the molecules.

Synthesis

Neil Bartlett demonstrated that dioxygenyl hexafluoroplatinate (O2PtF6), containing the dioxygenyl cation, can be prepared at room temperature by direct reaction of oxygen gas (O2) with platinum hexafluoride (PtF6):

:O2 + PtF6 →

The compound can also be prepared from a mixture of fluorine and oxygen gases in the presence of a platinum sponge at 450 °C, and from oxygen difluoride () above 400 °C:

:6 + 2 Pt → 2 +

At lower temperatures (around 350 °C), platinum tetrafluoride is produced instead of dioxygenyl hexafluoroplatinate.

is also found in similar compounds of the form O2MF6, where M is arsenic (As), antimony (Sb), gold (Au),{{cite book

The tetrafluoroborate and hexafluorophosphate salts may be prepared by the reaction of dioxygen difluoride with boron trifluoride or phosphorus pentafluoride at −126 °C:

:2 O2F2 + 2 BF3 → 2 O2BF4 + F2 :2 O2F2 + 2 PF5 → 2 O2PF6 + F2

These compounds rapidly decompose at room temperature: :2 O2BF4 → 2 O2 + F2 + 2 BF3 :2 O2PF6 → 2 O2 + F2 + 2 PF5

Some compounds including O2Sn2F9, O2Sn2F9·0.9HF, O2GeF5·HF, and O2[Hg(HF)]4(SbF6)9 can be made by ultraviolet irradiation of oxygen and fluorine dissolved in anhydrous hydrogen fluoride with a metal oxide.

All attempts to prepare with chloro anions like met with failure.

Reactions

The reaction of O2BF4 with xenon at 173 K produces a white solid believed to be F–Xe–BF2, containing an unusual xenon-boron bond:

:2 O2BF4 + 2 Xe → 2 O2 + F2 + 2 FXeBF2

The dioxygenyl salts O2BF4 and O2AsF6 react with carbon monoxide to give oxalyl fluoride, C2O2F2, in high yield.

References

References

1. 0-19-914633-0, {{ISBN. 978-0-19-914633-8, p. 355.
2. {{Greenwood&Earnshaw p. 616
3. {{Cotton&Wilkinson6th
4. (1968). "The vibrational frequency of the O₂⁺ cation". [[Journal of the American Chemical Society.
5. (1962). "Fluorides of the Noble Metals. Part II. Dioxygenyl hexafluoroplatinate(V), {{chem". [[J. Chem. Soc.]].
6. Bartlett, Neil. (1962). "Xenon hexafluoroplatinate(V), {{chem". [[Proc. Chem. Soc.]].
7. (1964). "The Preparation of Dioxygenyl Salts from Dioxygen Difluoride". [[J. Am. Chem. Soc.]].
8. (1975). "Vapour transport of dioxygenyl salts". [[J. Chem. Soc., Dalton Trans.]].
9. (1964). "New Dioxygenyl Compounds". [[Inorg. Chem.]].
10. (2020-02-03). "Syntheses of Dioxygenyl Salts by Photochemical Reactions in Liquid Anhydrous Hydrogen Fluoride: X-ray Crystal Structures of α- and β-O₂Sn₂F₉, O₂Sn₂F₉·0.9HF, O₂GeF₅·HF, and O₂[Hg(HF)]₄(SbF₆)₉". Inorganic Chemistry.
11. (1972). "Reaction of xenon with dioxygenyl tetrafluoroborate. Preparation of FXe-BF₂". Journal of the American Chemical Society.
12. (2001). "The reaction of dioxygenyl salts with {{su". Journal of Fluorine Chemistry.