Materials Data on Sr2AlGaNi2O7 by Materials Project
Sr2Ni2GaAlO7 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.39–3.17 Å. In the second Sr2+ site, Sr2+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Sr–O bond distances ranging from 2.39–2.48 Å. There are two inequivalent Ni2+ sites. In the first Ni2+ site, Ni2+ is bonded to six O2- atoms to form distorted NiO6 octahedra that share a cornercorner with one AlO6 octahedra, corners with four equivalent NiO6 octahedra, a cornercorner with one GaO4 tetrahedra, edges with two equivalent AlO6 octahedra, and a faceface with one AlO6 octahedra. The corner-sharing octahedra tilt angles range from 42–57°. There are a spread of Ni–O bond distances ranging from 1.98–2.63 Å. In the second Ni2+ site, Ni2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ni–O bond distances ranging from 1.98–2.65 Å. Ga3+ is bonded to four O2- atoms to form GaO4 tetrahedra that share a cornercorner with one NiO6 octahedra and corners with two equivalent GaO4 tetrahedra. The corner-sharing octahedral tilt angles are 29°. There are a spread of Ga–O bond distances ranging from 1.86–1.92 Å. Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one NiO6 octahedra, corners with four equivalent AlO6 octahedra, edges with two equivalent NiO6 octahedra, and a faceface with one NiO6 octahedra. The corner-sharing octahedra tilt angles range from 46–57°. There are a spread of Al–O bond distances ranging from 1.84–2.12 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to four equivalent Sr2+, one Ni2+, and one Ga3+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Sr2+, two equivalent Ni2+, and one Al3+ atom. In the third O2- site, O2- is bonded in a 5-coordinate geometry to one Sr2+, three Ni2+, and two equivalent Al3+ atoms. In the fourth O2- site, O2- is bonded to two Sr2+ and two equivalent Ga3+ atoms to form distorted corner-sharing OSr2Ga2 trigonal pyramids. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Sr2+, one Ni2+, and one Ga3+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to one Sr2+, two equivalent Ni2+, and one Al3+ atom. In the seventh O2- site, O2- is bonded in a 5-coordinate geometry to three Ni2+ and two equivalent Al3+ atoms.