Fig. 4: Crystal structure of Phase-Id BiNiO3.

a Refined NPD model showing the Pb11 unit cell of the structure, where the green, orange and cyan spheres represent Ni, Bi atom and 6s2 electrons (when Bi3+ states are present at Bi sites), respectively. b BiO12 polyhedra and Bi-O distances, where the orange and red spheres represent Bi and oxygen atoms, respectively.