The majority of the experimental NMR characterization and the corresponding theoretical simulations have been carried out for the ZSM-5 system, a zeolite with MFI topology but with the unit cell of a lower symmetry containing 24 T-sites. Hence, to allow one-to-one comparison to these data, we also adopted the H-ZSM-5 zeolite model which was directly obtained from the IZA database, 37 considering all T-sites (with Si/Al = 95) and a fully hydrated ZSM-5 zeolite structure at 350 K to closely replicate experimental conditions. The 27 Al chemical shifts predicted by the KRR method and averaged over the NNP-driven MD simulations for each of the 24 T-sites are presented in Table and span a range of 6.6 ppm. These predictions can be directly compared with the works of Holzinger et al. and Sklenák et al. , who have both calculated chemical shift values for every T-site and compared them with experimental Al NMR data in the H-ZSM-5 zeolite. Firstly, there is a sizable discrepancy with respect to the range of the experimental (and DFT-calculated) chemical shifts provided by Sklenák et al., which is about 10 ppm. However, Sklenák et al. considered H-ZSM-5 samples with much higher aluminium content, with Si/Al ratios of 15 and 22.5. At higher aluminium content the aluminium atoms are more closely spaced, which may lead to broadening of the range covered by the chemical shifts as illustrated in the previous Section 3.4. To test this hypothesis, we constructed a series of 45 models (adopting MFI unit cell with 12 types of T-sites for simplicity). These 45 models contained randomly placed aluminium atoms with Si/Al ratios ranging from 15 to 23 and were subsequently loaded with 17 water molecules per unit cell. The resulting range of calculated Al chemical shift values was found to be 11 ppm, which closely approximates the experimental range reported in the cited study (see Section S11 in ESI † for details). Based on these findings we suggest that such a broad range of experimental Al chemical shifts can be attributed to the presence of nearby aluminium atoms in the framework, especially for low Si/Al models. In fact, the breadth of the chemical shifts may even serve as a novel approach to probe aluminium proximity in the experimental ZSM-5 samples. This observation is supported by comparing the current prediction with the work of Holzinger et al. who have conducted a thorough study using ZSM-5 samples with a Si/Al ratio of 140, which has a high probability of containing mostly isolated aluminium atoms. The range of experimental values observed was 6.5 ppm, which is very similar to the 6.6 ppm range predicted by the KRR method.