All calculations used the CP2K DFT code, version 7.1, as installed on the HLRN-IV facilities of the North-German Supercomputing Alliance. The Perdew-Burke-Ernzerhof exchange-correlation functional was used together with the pairwise D3 dispersion correction developed by Grimme and co-workers (PBE-D3), in keeping with previous studies. All calculations used a plane wave energy cutoff of 600 Ry. Only the Γ point was considered in the sampling of the first Brillouin zone. Goedecker-Teter-Hutter pseudopotentials devised by Krack were used to represent core electrons. The structure optimizations made use of "molecularly optimized" (MOLOPT) Gaussian triple-zeta basis sets (TZVP for H, C, N, O, F, Si, TZVP-SR ["short range"] for Co in NON). Spinrestricted calculations were performed for all systems, including the Co 3+ -containing NON, as the cobaltocenium cation is diamagnetic. In the structure optimizations, all atomic coordinates and the unit cell parameters were optimized, fixing the symmetry of the unit cell to that of the respective crystal system. Optimizations were considered converged when the following criteria were met: Maximal geometry change = 5•10 -5 bohr, maximal residual force = 1•10 -6 Ha bohr -1 , maximal pressure deviation = 0.001 GPa.