For the MFI model with 1 water molecule per unit cell, the Al chemical shift stays almost constant across the entire temperature range considered. However, for MFI models with 2, 3, and 17 water molecules per unit cell, a consistent and significant decrease of 1.5 ppm is observed with increasing temperature. The latter phenomenon can largely be attributed to changes in the average T-O-T angles, which increase by approximately two degrees with rising temperature. This increase in angle is likely an indirect consequence of the change in dynamics of water molecules -as the temperature rises, the average water distance from the oxygen atoms next to the aluminium atom increases, leading to a more relaxed Al environment with larger T-O-T angles (see Table in ESI †). The slight increase in chemical shift observed for the model with two water molecules between 250 K and 300 K can be attributed to a minor decrease in bond length during this temperature range, which leads to the observed increase in chemical shift (see Fig. ). This may also be linked to variations in the trend of hydrogen atom distances to framework oxygen, as shown in Table †.