Structural studies of nitrogen, oxygen and halogen compounds

The interaction of nitrogen oxides N₂O, NO, N₂O₃, NO₂(N₂O₄) and N₂O₅ and the oxyhalides NOC1 and NO₂C1 with peroxydisulphuryldifluoride S₂O₆F₂ and bromine (1) fluorosulphate is studied under various conditions. The solid compounds NOSO₃F and NO₂SO₃F obtained were investigated via vibrational spectroscopy and solution studies. The non-spherical cations are found to cause a splitting of the E modes in S0₃F⁻ ion. Subsequently a whole range of fluoro complexes with nitrogen heterocations were studied and their vibrational spectra recorded. These include the cations NO⁺ , NO₂⁺ , N₂F₃⁺ and ONF₂⁺ and the anions AsF₆⁻ , SbF₆⁻, Sb₂F₁₁⁻ and SnF₆²⁻ . Noticeable anion-cation interaction appears to be absent for these compounds even though some minor departures from ideal behaviour are noted such as the splitting of degenerate modes for the octahedral anion (e.g. v₅F₂g). Vibrational frequencies for the N₂F₃⁺ and ONF₂⁺ cations have been assigned. The vibrational spectra of covalent fluorosulphates such as halogen fluorosulphates (where Hal = F, C1, Br), Br(0S0₂F) ₂⁻, CF₃S0₃F, NF₂SO₃F and S₂O₆F₂ are recorded. The halogen fluorosulphates have Cs symmetry, whereas C₂ symmetry is indicated for S₂O₆F₂. Finally ¹⁴N chemical shifts of some nitrogen-oxygen and halogen compounds have been measured and reported. It is found that the variation in the chemical shifts of these compounds is either due to the changes in the orbital angular momentum, or to the presence of low lying excited states or to a combination of both these effects.Science, Faculty ofChemistry, Department ofGraduat