Of the considered topologies, IWW is the strongest example of the general germanium distribution patterns discussed in the section 3.1, i.e., a strong preference for D4R occupation at low Ge loading, which is overcome by the tendency of germanium to cluster irrespective of the T-site position at high Ge loading. Up to Si/Ge ≈ 3-4, the germanium occupies predominantly the D4Rs units (Figure ) exhibiting an extremely large asymmetry in occupation of the four D4R units present in the unit cell, with two of the D4Rs rich in germanium (with up to ≈ 6-7 and 3-4 Ge atoms, respectively) while the other two are almost completely devoid of germanium, containing on average less then one germanium atom per D4R unit (see Figures and. For these relatively high Si/Ge ratios, the largest fraction of the germanium in other-than-D4R T-sites are located in between these two neighbouring germanium-rich D4Rs (SI Figure ), with some preference for the occupation of the S4R (composed of T12 and T16 sites) unit in the framework. For Si/Ge ≤ 3 the distribution pattern changes abruptly, favouring the forma- tion of germanium-rich layers co-planar with [0b0] plane (see, e.g., Figure for Si/Ge = 2.5). With increasing the germanium content even further these germanium-rich layers become thicker, encompassing the two neighbouring D4Rs including the framework and adjacent T-sites in between. In other words, for very low Si/Ge ratios, one obtains a structure composed of phaseseparated germanium-rich and germanium-poor layers co-planar with the [0b0] plane (see SI Figure ).