An Exploration of Bonding in V_1−x Mo_x O_2 (x ≤ 0.53) and Other Compounds

Transition metal solid-state compounds have received much attention due to their vast array of novel functional properties. However, their use is often impeded by an insufficient understanding of the structure-property relationship. This dissertation examines bonding in two families of transition metal compounds to elucidate connections to their electronic properties, V({1-x})Mo({x})O(2) and ZrSi. The primary focus was to understand the effects of strong metal--metal bonding on the structural disorder in V({1-x})Mo(_{x})O(_2), using a detailed analysis of total x-ray scattering data. This investigation established that strong metal--metal bonding enhances short-range correlations in the rutile phase while suppressing long-range correlations in the low-temperature phases, which is also accompanied by the suppression of the transition temperature and magnitude of the lattice anomaly. Together, these findings indicate that the disruption of long-range three-dimensional order can now be seen as the result of geometric frustration. This explains VO(_2)'s negative lattice anomaly. The total collapse of long-range three-dimensional order seems to occur around the same concentration that the lattice anomaly switches sign, identifying it as a potential order parameter. This also implies that the M1 phases of VO(_2) and MoO(_2) are distinct. The exploration of bonding in ZrSi resulted in a revised crystal structure of (\beta)-ZrSi (space group (Cmcm)) from single-crystal x-ray diffraction data, correcting the atomic position and bond distances. The revised Si--Si bond length has been modified substantially from 2.723(6) Å to 2.4411(8) Å. Additionally, a comprehensive analysis of bonding trends in early transition metal compounds closely related to FeB-type (\alpha)-ZrSi and CrB-type (\beta)-ZrSi was completed, using electronic structures calculated by the Linear Muffin-Tin Orbital (LMTO) method.