UOV with Si/Ge ≈ 3 was reported to successfully transform into a new IPC-12 structure (UOV layers connected with the oxygen bridges only) using the ADOR strategy. However, the hydrolyzed intermediate could not be swollen 5 using the surfactant and a strong signal corresponding to F -anions present in purely siliceous D4R units was present in the 19 F MAS NMR spectra, all of which indicate a heterogeneity in germanium population across the D4R units. This is broadly in agreement with our simulations which predict the presence of Ge-rich and Ge-poor D4Rs units for UOV with Si/Ge < 6-7 (Figures and SI Figures S20 S33). Also, we predict a significant population of germanium in the UOV layers at least for Si/Ge < 3-4 (Figure ), which is consistent with the observed 52 lability of the UOV framework at ambient conditions at very low Ge loadings (Si/Ge ≈ 1.4) leading to a loss of crystallinity and formation of GeO 2 . Yet, Kasneryk et al. showed that even a modest change in one of the synthesis parameters (Si/Ge ratio in the synthesis gel) -which does not change the Si/Ge ratio of the final UOV samples -can lead to nonnegligible effects on the 19 F MAS NMR spectra and the propensity of UOV to undergo ADOR transformation. This is presumably a consequence of some differences in the Ge distributions between these UOV samples, the origin of which is, as discussed in detail above (Section 3.4), beyond the prediction capabilities of the models adopted herein.