Whereas diffraction measurements deliver information about the long-range structure, NMR methods can probe the local environment. F-NMR measurements have been widely used to prove the incorporation of fluoride into d4r cages, as it is associated with distinct 19 F chemical shifts. Moreover, NMR can deliver insights into the preferential local arrangements of different elements at the corners of the cage, e.g., in mixed (Si,Ge)O2 zeotypes. Electronic structure methods in the framework of density functional theory (DFT) have been employed to study different aspects of fluoride-containing d4r units, such as the nature of the chemical bonding, characteristic features in vibrational spectra, the mechanism of fluoride removal from the d4r cage, and the relationship between different local arrangements of Si and Ge at the corners of the cage and the resulting F and Si chemical shifts. In a previous investigation by one of us, DFT structure optimisations and DFT-based ab initio molecular dynamics (AIMD) calculations were used to study the local environment and fluoride dynamics in AST-type germanosilicates. It was found that the fluoride anions reside at the cage centre in the pure end members SiO2-AST and GeO2-AST, but that they are displaced towards one Ge atom, or towards Ge-O-Ge edges, in mixed (Si,Ge)O2 systems, often forming directional Ge-F bonds with a length of 2.2 to 2.4 Å. The formation of these bonds leads to a reduction in the freedom of motion that is clearly visible in the root mean square displacements (RMSDs) of fluoride, and in the F-Ge radial distribution functions (RDFs). Building on this previous study, the present work uses an analogous methodological approach to investigate several new aspects: