To determine relationships between the size and shape of A + and the resulting network distortions (Fig. ), atomic coordinates from SCXRD data at 300 K were used to extract the geometry of A + . Following previous reports, we use the globularity (G) as a measure for the asphericity of A + , where G = 1 for a sphere. For this, we used DFT calculations to obtain the A + surface (Sm,A+), the A + volume (VA+) as enclosed by Sm,A+, and the surface of an idealised sphere (Ssp,A+) with VA+ (Table ). Then, the A + globularity (G = Ssp,A+/Sm, sp,A+) was calculated (Table ). By using CrystalExplorer17, we obtained G > 0.8 for all A + , which agrees with previous results from the literature for A + of dicyanamide-based molecular perovskites. A similar trend in G with slightly smaller values is obtained when using Gaussian16 for calculating Sm,A+, Ssp,A+ and VA+, see SI for details (Table and). No correlation between Ap, VA+ and G is observed (Table ). Hence, small alkyl chain modifications on the nitrogen atom of piperidinium, and thus its shape, evidently have an impact on Ap of the 3D [Ni(C2N3)3] -network (Fig. ) and, as we will see in the following, on the resulting pressure responsiveness.