Materials Data on CrGa3(CoSe4)2 by Materials Project
CrGa3(CoSe4)2 crystallizes in the monoclinic Cm space group. The structure is two-dimensional and consists of two CrGa3(CoSe4)2 sheets oriented in the (1, 0, 0) direction. Cr3+ is bonded to four Se2- atoms to form CrSe4 tetrahedra that share corners with three GaSe6 octahedra, corners with two equivalent CrSe4 tetrahedra, and corners with four equivalent GaSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–57°. There are a spread of Cr–Se bond distances ranging from 2.42–2.47 Å. There are two inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded to four Se2- atoms to form CoSe4 tetrahedra that share corners with three GaSe6 octahedra and corners with six CoSe4 tetrahedra. The corner-sharing octahedral tilt angles are 58°. There are a spread of Co–Se bond distances ranging from 2.31–2.34 Å. In the second Co2+ site, Co2+ is bonded to four Se2- atoms to form CoSe4 tetrahedra that share corners with three GaSe6 octahedra and corners with six CoSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–57°. There are one shorter (2.30 Å) and three longer (2.31 Å) Co–Se bond lengths. There are three inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to six Se2- atoms to form GaSe6 octahedra that share a cornercorner with one GaSe4 tetrahedra, corners with two equivalent CrSe4 tetrahedra, corners with three CoSe4 tetrahedra, and edges with six GaSe6 octahedra. There are a spread of Ga–Se bond distances ranging from 2.60–2.66 Å. In the second Ga3+ site, Ga3+ is bonded to six Se2- atoms to form GaSe6 octahedra that share a cornercorner with one CrSe4 tetrahedra, corners with two equivalent GaSe4 tetrahedra, corners with three CoSe4 tetrahedra, and edges with six GaSe6 octahedra. There are a spread of Ga–Se bond distances ranging from 2.59–2.64 Å. In the third Ga3+ site, Ga3+ is bonded to four Se2- atoms to form GaSe4 tetrahedra that share corners with three GaSe6 octahedra, corners with two equivalent GaSe4 tetrahedra, and corners with four equivalent CrSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–57°. There are three shorter (2.44 Å) and one longer (2.45 Å) Ga–Se bond lengths. There are eight inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to one Cr3+ and two equivalent Ga3+ atoms. In the second Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to two equivalent Cr3+ and one Ga3+ atom. In the third Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to three Co2+ atoms. In the fourth Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to three Co2+ atoms. In the fifth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to one Cr3+ and three Ga3+ atoms. In the sixth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to four Ga3+ atoms. In the seventh Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to one Co2+ and three Ga3+ atoms. In the eighth Se2- site, Se2- is bonded to one Co2+ and three Ga3+ atoms to form distorted corner-sharing SeGa3Co trigonal pyramids.