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-xMo_xO₂ and ZrSi. The primary focus was to understand the effects of strong metal--metal bonding on the structural disorder in V_1-xMo_xO₂, 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 VO₂'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 VO₂ and MoO₂ are distinct. The exploration of bonding in ZrSi resulted in a revised crystal structure of β-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 α-ZrSi and CrB-type β-ZrSi was completed, using electronic structures calculated by the Linear Muffin-Tin Orbital (LMTO) method.

Grantor dc:publisher

University of Alabama Libraries

Year dc:date.issued

2022

Author dc:creator

• Douglas, Tyra

Advisor dc:contributor.advisor

• Allred, Jared M.

Contributors dc:contributor

• Gupta, Arunava
• Szulczewski, Gregory J
• Rupar, Paul A
• Weaver, Mark L

Statement dc:rights

• All rights reserved by the author unless otherwise indicated.

Language dc:language.iso

en_US, English

Dc Identifier Other

http://purl.lib.ua.edu/184315
u0015_0000001_0004364
Douglas_alatus_0004D_14729

OAI identifier oai:identifier

oai:ir.ua.edu:123456789/8582