Materials Data on Sr(NiO2)4 by Materials Project
Sr(NiO2)4 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Sr2+ is bonded in a distorted hexagonal planar geometry to six equivalent O2- atoms. All Sr–O bond lengths are 2.52 Å. There are two inequivalent Ni+3.50+ sites. In the first Ni+3.50+ site, Ni+3.50+ is bonded to six equivalent O2- atoms to form edge-sharing NiO6 octahedra. All Ni–O bond lengths are 2.02 Å. In the second Ni+3.50+ site, Ni+3.50+ is bonded to six O2- atoms to form edge-sharing NiO6 octahedra. There is four shorter (1.89 Å) and two longer (1.91 Å) Ni–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to one Sr2+ and three Ni+3.50+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to three equivalent Ni+3.50+ atoms.