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Perovskite-type compounds are among the most important of inorganic solid-state materials, and exist in a wide variety of compositions with related crystal structures. These variations allow perovskite-type materials to display many important and useful properties, such as superconductivity, dielectrics, and colossal magnetoresistance. A primary goal of this thesis is to prepare an oxyfluoride analog of (Ca, La)MnO3, known for its colossal magnetoresistive properties, and determine the effect of anion substitution on the magnetic properties of this material. The novel compound targeted for synthesis in this study is Ca2Mn2O5F, which achieves a mixed Mn+3/Mn+4 oxidation in the lattice via anion rather than cation substitution, as is the usual case. This mixed oxidation is an important feature of manganite oxides displaying colossal magnetoresistance. A four-step process was proposed in order to synthesize the target oxyfluoride compound, and will be described in detail. While the first step was successfully completed, subsequent steps were not. These attempts will be summarized along with the conclusions from this study and suggestions for future work.A second project discussed in this thesis is the Research Experiences to Enhance Learning (REEL) project, based on a state-wide initiative centered at the Ohio State University to introduce meaningful research experiences into the first and second year chemistry curriculum The YSU-developed REEL modules focus on perovskite-type compounds, and specifically for this study on solid solutions of KCuF3 with KNiF3 and KMnF3. Thus the focus of the work was on the two series of compositions, K(CuxNi1-x)F3 and K(CuxMn1-x)F3 for x = 0, 0.1, 0.2 …0.9, 1.0. These two sets of compounds were prepared by students enrolled in the second semester general chemistry laboratory course during the Spring 2010 and Fall 2010 semesters. Students analyzed their compounds using X-ray Powder Diffraction (XRPD), UV-Vis Spectrometry, and X-ray Fluorescence (XRF) techniques under the guidance of this thesis author. The final data was then further analyzed and quantitatively refined in this study using Rietveld powder refinement methods. From the results, the solubilities of the cubic KNiF3 and KMnF3 phases in tetragonal KCuF3 were determined, and compared to results of previous studies on the K(CuxCo1-x)F3 and K(CuxMg1-x)F3 systems.

Relative to oxides, mixed anion materials containing N and/or F dissolved within an oxide lattice offer a variety of advantages, including smaller band gaps and incorporating a greater variety of potential cations with a larger possible range of oxidation states. These factors, coupled with the relatively lowered symmetry that may occur due to anion ordering suggest enhanced dielectric, magnetic, and/or optical properties for the targeted materials. The goal of this project is to synthesize a mixed-anion analog of (Ca, La)MnO3, which is well known for colossal magnetoresistive properties due in part to the presence of both Mn3+ and Mn4+ in the lattice. Such materials may have potential applications in magnetic storage devices (e.g. computer hard drives). Whereas the presence of mixed Mn3+/4+ ions results from substituting La3+ for some Ca2+ in the oxide lattice, the same effect can hypothetically be achieved through anion substitutions such as N3- and/or F- for O2-. Attempts were made in this study to directly synthesize novel CaMnNxOyFz materials from binary Mn and Ca compounds, or from redox reactions in N2, but they were unsuccessful. These attempts will be summarized and a new approach involving ammonolysis of CaMnO3, followed by fluorination of the product to give the novel compound Ca2(Mn3+, Mn4+)O5F, will be discussed. A second project will also be discussed involving crystal chemical studies of Sr2BiGa11O20. The single crystal X-ray structure of the compound, which is found to be isostructural with Ba2BiGa11O20, is presented for the first time. The structure will also be discussed in the context of a bond-valence sum analysis.