Tregenna-Piggott, Philip Louis William;
(1994)
Metal(III)-water interactions.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
This thesis is devoted to the study of metal(III)-water interactions by a variety of physical techniques. Studies are undertaken in the solid state where the tervalent hexa-aqua-cation is held rigidly within the lattice, thus facilitating its study. The RbMᴵᴵᴵ(SO₄)₂.12H₂O alums, where Mᴵᴵᴵ is Al, Ga, In, Ti, V, Cr, and Fe, have been characterised by Raman spectroscopy. The Ti and V rubidium alums are of a different structural modification to the other alums studied. This is related to a change in the mode of water co-ordination leading to a larger trigonal field stabilisation energy for the Ti and V hexa-aqua-cations. The Raman spectra of the RbTi(SO₄)₂.12H₂O alum are anomalous. Soft modes are observed indicating the onset of a phase transition. The Raman spectra are interpreted in conjunction with the published EPR and magnetic data for the [Ti(OH₂)₆]³⁺ cation. A model in which the [Ti(OH₂)₆]³⁺ cation is subject to a dynamic Jahn-Teller distortion, freezing out into a static distortion at temperatures approaching 4 K, is proposed. A polarised neutron diffraction experiment has been performed on CsMo(SO₄)₂.12D₂O. This is the first report of such a study for any tervalent hexa-aqua-cation. Information on the spatial spin distribution within the [Mo(OD₂)₆]³⁺ cation is obtained. Spin density is found to occupy t2g-like orbitals on the metal with some spin transferred to the ligand where it is concentrated in a molecular orbital normal to the plane of the water molecule. Negative spin is also found in the molybdenum-oxygen bonding region indicative of electron correlation effects. These observations are interpreted in terms of simple concepts of chemical bonding.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Metal(III)-water interactions |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Thesis digitised by ProQuest. |
| Keywords: | Pure sciences; Hexa-aqua-cation |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10106214 |
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