Polyatomic cations of group 16 elements

Compounds containing 02 cation 340 are colorless with the exception of 02+PtF6, which is red due to the PtF6 ion. The compound 02+PF6 decomposes slowly at 80°C862 and rapidly at room temperature, giving oxygen, fluorine, and phosphorous pentafluoride. 18F tracer studies on 02+BF4 have led to the conclusion that the mechanism of the decomposition involves the equilibrium [Eq. (4.216)] followed by a bimolecular decomposition of 02F.863 

Dioxygenyl hexafluoroantimonate has been studied by differential thermal analysis.864 Decomposition of 02+SbF,s proceeds in two stages, according to the mechanism given in Eqs. (4.217) and (4.218). 

The C)2 1 Sh2I i i was converted to 02+SbI fi by heating at 130°C in vacuo conversely, 02+Sb2Fn- was prepared by reaction of 02 1 SbFfi and SbF5 at 180-200°C. Dioxygenyl hexafluoroarsenate is markedly less stable than the hexafluoroantimonate salts it decomposes rapidly at 130-180°C. 02 1 PtF(, can be sublimed above 90°C in vacuo and melts with some decomposition at 219°C in a sealed tube.863 

X-ray powder data obtained from the cubic form of 02PtF6 were consistent with the presence of 02+ and PtFfi ions.863 The structure was refined using neutron diffraction powder data. The 02+ cation 340 resembles nitrosonium ion.864 The IR, Raman, and ESR spectra of 02+ salts have been studied in detail.865-868 

Recently, the X-ray crystal structures of 02+MF6 salts (M = Sb, Ru, Pt, Au) have been determined.869 For the 02+ cation in the 02+RuF6 salt, an interatomic 0—0 bond distance of 1.125 A was found at — 127°C870 in agreement with the gas-phase value of 1.1227 A.857 Values obtained for the 0—0 bond length in the 02+AuF6 salt are 1.068 A(-122°C) and 1.079 A.871 872 

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