Structural characterization of complex inorganic materials using solid-state NMR spectroscopy

Abstract: Over the past decades, advancements in technology have relied greatly on the development of new functional inorganic materials. Detailed structural characterization of these materials is key for the understanding and also prediction of chemical and physical properties. The structural characterization of complex inorganic materials is typically conducted by a combination of multiple methods. Solid-state NMR brings several advantages because it is element-specific, non-destructive and allows local-chemical-structure elucidation for composite materials, disordered and interfacial structures. This thesis focuses on the application of solid-state NMR for structural characterization of two classes of complex inorganic materials. Calcium phosphate cements (CPCs) have been widely applied as bone-substitution materials. The structures of the setting cements are vital for understanding their behaviors in setting and bone-regeneration processes and functions of different additives. In this thesis two types of CPCs, with different additives, were investigated. The different components in the cements could be identified and quantified with solid-state NMR. Correlation spectra were established that helped in probing the structural relationship between different phases. Mixed-anion perovskite compounds AB(O,X)3 (X = N, F, H, OH, etc.) have been intensively investigated because of their unique properties for different applications as introduced by the mixed anion environment for the transition metal component B. Because of the lability of hydride oxyhydrides emerged as versatile precursors for the synthesis of other mixed-anion compounds and oxynitrides are extensively investigated for their photocatalytic activity and dielectric properties. In this thesis the oxyhydrides BaTiO3-xHx and SrVO2H were synthesized and their subsequent conversions to oxynitrides were investigated. Solid-state NMR was used to probe the local chemical environments of H and N incorporated in the perovskite anion substructure. 1H NMR proved especially to be useful in the quantification of H which is very difficult to accomplish by other methods.