Fig. 2.

Schematic of the bond-disproportionation modes in the NNO bilayer (${\mathrm{N}\mathrm{N}\mathrm{O}}_2$/${\mathrm{N}\mathrm{A}\mathrm{O}}_2$) and its propagation into nearby NAO layers, projected on the Ni–Ni and Ni–Al direction, as discussed in the main text for a bilayer structure with the average Q = 0.078 Å—similar to the Q of the experimental bulk low T structure.