Though linear trends across all nine compounds were not observed, the lowering of Tm is in general consistent with larger values of ΔSf, themselves ascribed to the progressively more restricted conformations of the larger organic cations in the solid state. This is consistent with the rational adopted by Mason et al in their network-forming bis(acetamides). Any trends in ΔHf and alkyl chain length are less clear, though are not perhaps expected given the proposal that melting does not directly involve bond breaking within the alkylammonium cation itself, but rather the M-N coordination bonds in the surrounding framework (Fig. ).