Compared to the TMA-containing system, the F-Si RDFs of SiO2-AST_QNU show some rather intricate differences, with more prominent "shoulders" at both smaller and larger F-Si distances that are best visible at 150 K. This observation can be attributed to a certain off-centre displacement of fluoride. The slight change in the equilibrium location is hardly visible in the average structures (Figure ), but it becomes more apparent when looking at the trajectory of an individual fluoride anion (lower part of