Materials Data on Ca4NbGaO8 by Materials Project

Ca4NbGaO8 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are four inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.40–3.06 Å. In the second Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.29–2.74 Å. In the third Ca2+ site, Ca2+ is bonded in a 5-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.28–3.06 Å. In the fourth Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted CaO6 octahedra that share corners with three equivalent NbO6 octahedra and corners with three equivalent GaO4 tetrahedra. The corner-sharing octahedra tilt angles range from 19–24°. There are a spread of Ca–O bond distances ranging from 2.24–2.51 Å. Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with two equivalent NbO6 octahedra, corners with three equivalent CaO6 octahedra, and a cornercorner with one GaO4 tetrahedra. The corner-sharing octahedra tilt angles range from 19–33°. There are a spread of Nb–O bond distances ranging from 1.91–2.15 Å. Ga3+ is bonded to four O2- atoms to form GaO4 tetrahedra that share a cornercorner with one NbO6 octahedra and corners with three equivalent CaO6 octahedra. The corner-sharing octahedra tilt angles range from 34–73°. There are a spread of Ga–O bond distances ranging from 1.84–1.92 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+, one Nb5+, and one Ga3+ atom. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Ca2+ and one Ga3+ atom. In the third O2- site, O2- is bonded in a tetrahedral geometry to three Ca2+ and one Ga3+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and two equivalent Nb5+ atoms. In the fifth O2- site, O2- is bonded in a 5-coordinate geometry to five Ca2+ and one Nb5+ atom. In the sixth O2- site, O2- is bonded in a 6-coordinate geometry to five Ca2+ and one Nb5+ atom. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Ca2+ and one Ga3+ atom. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to four Ca2+ and one Nb5+ atom.