Materials Data on Ga2NiO4 by Materials Project

NiGa2O4 is Spinel-like structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are two inequivalent Ni2+ sites. In the first Ni2+ site, Ni2+ is bonded to four O2- atoms to form NiO4 tetrahedra that share corners with three equivalent NiO6 octahedra and corners with nine equivalent GaO6 octahedra. The corner-sharing octahedra tilt angles range from 56–60°. There is three shorter (1.96 Å) and one longer (2.00 Å) Ni–O bond length. In the second Ni2+ site, Ni2+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with three equivalent NiO4 tetrahedra, corners with three equivalent GaO4 tetrahedra, and edges with six equivalent GaO6 octahedra. There are three shorter (2.05 Å) and three longer (2.08 Å) Ni–O bond lengths. There are two inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to six O2- atoms to form GaO6 octahedra that share corners with three equivalent NiO4 tetrahedra, corners with three equivalent GaO4 tetrahedra, edges with two equivalent NiO6 octahedra, and edges with four equivalent GaO6 octahedra. There are a spread of Ga–O bond distances ranging from 1.96–2.07 Å. In the second Ga3+ site, Ga3+ is bonded to four O2- atoms to form GaO4 tetrahedra that share corners with three equivalent NiO6 octahedra and corners with nine equivalent GaO6 octahedra. The corner-sharing octahedra tilt angles range from 57–58°. There is three shorter (1.90 Å) and one longer (1.96 Å) Ga–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to one Ni2+ and three Ga3+ atoms to form a mixture of distorted edge and corner-sharing OGa3Ni trigonal pyramids. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Ga3+ atoms. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ni2+ and two equivalent Ga3+ atoms. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ni2+ and three equivalent Ga3+ atoms.