The Electronic Structure of Some Second Row Elements in High Oxidation States

Webster, Brian C (1967) The Electronic Structure of Some Second Row Elements in High Oxidation States. PhD thesis, University of Glasgow.

Abstract

The core of the studies presented here is the calculation of numerical self consistent field wave functions for the second row elements Si, P, S, Cl and Ar in excited configurations which involve the 3d orbital. In many discussions of the bonding in molecules which contain these elements as their central atoms,it si maintained that the 3d orbital may have an important role. To take a classic example,on the basis of the concept of hybridisation Pauling has interpreted the bonding in sulphur hexafluoride in terms of the formation by the sulphur atom of sp3d2 hybrids. Later it was observed that the maximum in the 3d wave function, if taken to be of a Slater type, lay well beyond the S-F internuclear distance. On further investigation, the use of the Slater 3d orbital in this context was judged to be quite acceptable and an elaborate theory was developed to bring the 3d orbital into a form suitable for bonding. This situation persisted to the time this work was commenced,though on occasions it had been suggested that perhaps the Slater 3d orbital is not a suitable representation for the 3d wave function of S(sp3d2). In the opening chapter of this thesis,the course of such disputations is placed in perspective against a background of the chemical thought prevailing at the period and the problems involved are formulated. For a satisfying solution it is found to be necessary to perform a series of self consistent field calculations,and to investigate more fully the concept of the valence state. Chapter II treats in detail the theory of the self consistent field and the manner in which atomic calculations are performed. This is followed by a study of the valence state concept utilising the theory of the symmetric permutation group. Some very interesting results are obtained. The subsequent two chapters are concerned with the shape and energy of the valence orbitals possessed by the elements mentioned when in high oxidation states. It is discovered that many affirmations which have been made on the subject of the 3d orbital are unfounded and indeed quite erroneous. This is rather surprising in view of the admirable investigations performed on this topic by Craig and his collaborators during the past decade. Their theories are therefore closely examined in Chapter VI and discrepancies explained. On reaching the closing pages it is possible to suggest in what manner a '3d orbital' might assume a role in the bonding of the second row elements under review. Finally a plea is made that the concept of hybridisation must now give way to the concept of polarisation if the development of chemical thought is not to be inhibited.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Physical chemistry, Computational chemistry
• Date of Award: 1967
• Depositing User: Enlighten Team
• Unique ID: glathesis:1967-78450
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 28 Feb 2020 12:09
• Last Modified: 28 Feb 2020 12:09
• URI: https://theses.gla.ac.uk/id/eprint/78450