In summary, we identified two phenomena driving the character of the germanium distributions in D4R-containing zeolites, the general clustering tendency of germanium and a specific preference of germanium towards occupation of D4R units. At low to intermediate germanium loading (approximately Si/Ge ≥ 5) the preference for D4R occupation is the main driving force, as it also allows for significant clustering at such loading. This is exemplified by the finding that the largest Ge-Ge CN values are calculated for D4R T-sites at such Si/Ge ratios (see SI Figures ). At high germanium loading (approximately Si/Ge < 5), the germanium clustering in T-sites other than in D4R units starts to be favoured significantly, slowing down or even diminishing the population of germanium in D4R units. In the following, we focus on the particular manifestation of these general trends for each specific topology as well as on the specific role of various topological features (such as heterogeneity of D4R units and topology dimensionality) on the germanium distributions.