Materials Data on MgCo3O7 by Materials Project
MgCo3O7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Mg–O bond distances ranging from 2.07–2.55 Å. In the second Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Mg–O bond distances ranging from 2.09–2.22 Å. There are six inequivalent Co4+ sites. In the first Co4+ site, Co4+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with three CoO6 octahedra and a cornercorner with one CoO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 46–70°. There are a spread of Co–O bond distances ranging from 1.74–1.84 Å. In the second Co4+ site, Co4+ is bonded to five O2- atoms to form distorted CoO5 trigonal bipyramids that share corners with two equivalent CoO6 octahedra, a cornercorner with one CoO4 tetrahedra, and an edgeedge with one CoO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 28–54°. There are a spread of Co–O bond distances ranging from 1.72–1.91 Å. In the third Co4+ site, Co4+ is bonded to five O2- atoms to form distorted CoO5 trigonal bipyramids that share corners with three CoO6 octahedra, a cornercorner with one CoO4 tetrahedra, an edgeedge with one CoO6 octahedra, and an edgeedge with one CoO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 41–64°. There are a spread of Co–O bond distances ranging from 1.76–2.10 Å. In the fourth Co4+ site, Co4+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with four CoO6 octahedra and a cornercorner with one CoO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 46–60°. There are a spread of Co–O bond distances ranging from 1.73–1.86 Å. In the fifth Co4+ site, Co4+ is bonded to six O2- atoms to form distorted CoO6 octahedra that share corners with three CoO4 tetrahedra, corners with three CoO5 trigonal bipyramids, an edgeedge with one CoO6 octahedra, and an edgeedge with one CoO5 trigonal bipyramid. There are a spread of Co–O bond distances ranging from 1.84–2.28 Å. In the sixth Co4+ site, Co4+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with four CoO4 tetrahedra, corners with two equivalent CoO5 trigonal bipyramids, and an edgeedge with one CoO6 octahedra. There are a spread of Co–O bond distances ranging from 1.82–2.00 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two Mg2+ and one Co4+ atom. In the second O2- site, O2- is bonded in a distorted tetrahedral geometry to two Mg2+ and two Co4+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+ and two Co4+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+ and two Co4+ atoms. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+ and two Co4+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Co4+ atoms. In the seventh O2- site, O2- is bonded in a trigonal planar geometry to one Mg2+ and two Co4+ atoms. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to two Mg2+ and one Co4+ atom. In the ninth O2- site, O2- is bonded in a bent 120 degrees geometry to two Co4+ atoms. In the tenth O2- site, O2- is bonded in a distorted L-shaped geometry to one Mg2+ and two Co4+ atoms. In the eleventh O2- site, O2- is bonded in a distorted trigonal planar geometry to three Co4+ atoms. In the twelfth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Co4+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Mg2+ and two Co4+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted T-shaped geometry to three Co4+ atoms.