Beryllates as functional materials

This thesis aims to study different application-related solid-state compound classes with the common denominator beryllium. Fundamental and applied investigations are combined, while various preparational and analytical methods are exercised. The Chapters 2-4 focus on oxonitridoberyllosilicates, their high-temperature synthesis and the importance of their respective structural characteristics for possible applications. The subsequent Chapters 5 and 6 cover ternary chalkogenidoberyllates. Herein, the synthesis as well as structure elucidation are discussed and, in case of Na$:2$BeS${}_2$, ion conduction properties are investigated. The following chapter intends to elaborate the scientific relevance of these findings in the context of current and possible future research in addition to the separate discussions in the respective chapters. The three major issues serve as a guide for the discussion: Oxonitridoberyllosilicates for pcLED Backlit Displays, beryllium in red pcLED Phosphors, thioberyllates in solid-state ion conduction. In this thesis the introduction of beryllium to oxides, nitrides and sulfides was shown to be highly promising in terms of structural chemistry and application. On the one hand, an actually applicable phosphor was found and on the other hand, pathways for future investigations on new compound classes were drawn. The structural diversity in oxonitridoberyllates and, in the broader context, Be-Si-Al-P-O-N-S-compounds allows for a broad variety of properties to be expected. Especially considering high-pressure investigations, it is obvious that the structural possibilities and feasible motifs are far from being studied completely. The understanding of network building structures and resulting properties based on the increased structural variety will subsequently lead to further expansion of solid-state chemistry.