We next focused on determining the properties of the six new hexagonally-packed TMA phases in more detail. For the hexagonally packed TMA structures, we observed differences in the crystallographic symmetry due to the stacking geometry of the hexagonal TMA networks. Among these structures, we found a close structural match between the predicted low-density polymorph, 1 (Figure ), and the two solvates; 1,4-dioxane/1,3-dimethoxybenzene (TMA_7-35) and 1-butanol/1,3-dimethoxybenzene (TMA_8-35) (SI, Figure ). Hence, even though solvent affects the packing of TMA molecules in these structures, we could identify crystal structures that closely match the predicted low-density polymorph, 1 (Figure ).