Materials Data on MgNi2O5 by Materials Project
MgNi2O5 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Mg2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Mg–O bond distances ranging from 2.06–2.41 Å. There are two inequivalent Ni4+ sites. In the first Ni4+ site, Ni4+ is bonded to five O2- atoms to form a mixture of corner and edge-sharing NiO5 trigonal bipyramids. There are a spread of Ni–O bond distances ranging from 1.82–1.98 Å. In the second Ni4+ site, Ni4+ is bonded to five O2- atoms to form a mixture of corner and edge-sharing NiO5 trigonal bipyramids. There are a spread of Ni–O bond distances ranging from 1.83–1.98 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Mg2+ and two Ni4+ atoms to form corner-sharing OMg2Ni2 tetrahedra. In the second O2- site, O2- is bonded in a distorted see-saw-like geometry to one Mg2+ and three equivalent Ni4+ atoms. In the third O2- site, O2- is bonded in a distorted see-saw-like geometry to one Mg2+ and three equivalent Ni4+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Mg2+, one Ni4+, and one O2- atom. The O–O bond length is 1.51 Å. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Mg2+, one Ni4+, and one O2- atom.