Date of Award
Open Access Dissertation
Chemistry and Biochemistry
Hans-Conrad zur Loye
The primary objective of this dissertation is to inform the reader about more thansixty new materials with potentially attractive physical properties obtained via molten alkali halide flux methods as X-ray diffraction quality crystals. Flux crystal growth carries several advantages over other synthetic methods, including low reaction temperatures and straightforward post-reaction workup. This dissertation consists of 11 chapters, including an introductory chapter, which are organized into two parts, each corresponding to the general structure type of the family of oxides and chalcogenides being investigated. Part 1, which encompasses chapters 2–6, is dedicated to the discussion of crystal growth of complex chalcogenides and their physical properties, in addition to uranium (IV) compounds that crystallized serendipitously. In contrast to chapters 3–6 that focus on molten flux crystal growth of materials, chapter 2 reports on the discussion of Rietveld refinement analysis of a series of uranium-containing lanthanide oxides prepared via hightemperature solid state route, and their magnetic properties. Chapter 3 addresses the serendipitous discovery of a family of uranium (IV) phosphates that crystallized in attempts to isolate complex uranium sulfides. Chapters 4–6 highlight the alkali halide flux synthesis and characterization of an array of quaternary and penternary sulfides, which are traditionally grown out of polychalcogenide melts.
Part 2, consisting of the last five chapters, will center on the density functional theory (DFT) guided synthesis and characterization of complex transition metal oxides crystallizing in the zeolite, hollandite, mayenite, and other new structure types. Chapter 7 discusses a series of structurally complex cobalt silicates and germanates that crystallize in porous three-dimensional framework structures. Chapter 8 reports on a family of new rubidium-containing mixed-metal titanium hollandites. This is the first report of rubidiumbased mix-metal titanium hollandite materials grown as highest quality single crystals. Chapter 9 focuses on polymorphism, DFT-guided and molten nitrate salt-assisted single crystal to single crystal ion exchange in zeotypic CsFeGeO4. Chapters 10 and 11, and Appendix A examine several Mg-, Ti-, Fe-, Ni- Cu-, Zn- and Ga-containing oxides and fluoride, crystallizing in new and known structures types, and their pertinent DFT calculations. Specifically, these materials include RbMgF3, Rb0.74Ga6.62Ti0.38O11, Rb2Co1.85Ge1.15O6, Sr-containing mayenite, layered KxTi2-yMyO4 (M = Fe, Ni, Cu, Zn), and RbFeTO4 (T = Si, Ge).
Usman, M.(2021). Molten Alkali Halide Salt-Flux Crystal Growth and Physical Property Determination of Complex Oxides and Chalcogenides Supported by First Principles Density Functional Theory Calculations. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/6318
Available for download on Monday, May 15, 2023