Substitution, Eigenschaften und neue Strukturen silicatverwandter nitridischer Verbindungen

The thesis is addressing different aspects of the chemistry of
silicate related nitridic compounds. One main focus was the
investigation of the influence of substitution (cations, O/N,
Si/Al, halides) on the material properties of the compounds. For
this concern known compounds (nitridosilicates, sions, sialons) as
well as a new class of compounds (oxonitridosilicate halides) were
investigated. Very important for these investigations was the
detailed characterisation of the synthesised compounds. In this
context the establishment of an especially optimised microprobe
technique has to be highlighted. The new technique allows the
quantitative analyses of light elements as O, N, Cl and Si, Al, Br
beside elements like Sr, Ba and the lanthanides. In addition a lot
of different analytical tools were used to understand the crystal
chemistry of the investigated systems, e.g. single-crystal x-ray
analyses, powder neutron diffraction, XAS, EDX and spectroscopic
methods, some of them also performed under high pressure. The
second main focus of the work was the synthesis and
characterisation of compounds with new crystal structures in the
area of oxonitridosilicates, sions and sialons.