Materials Data on CrGa3(FeSe4)2 by Materials Project
CrGa3(FeSe4)2 crystallizes in the monoclinic Pm space group. The structure is two-dimensional and consists of one CrGa3(FeSe4)2 sheet oriented in the (0, 0, 1) 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 octahedral tilt angles are 57°. There are a spread of Cr–Se bond distances ranging from 2.43–2.50 Å. There are two inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to four Se2- atoms to form FeSe4 tetrahedra that share corners with three GaSe6 octahedra and corners with six FeSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 57–58°. There are a spread of Fe–Se bond distances ranging from 2.37–2.42 Å. In the second Fe2+ site, Fe2+ is bonded to four Se2- atoms to form FeSe4 tetrahedra that share corners with three GaSe6 octahedra and corners with six FeSe4 tetrahedra. The corner-sharing octahedral tilt angles are 58°. There are a spread of Fe–Se bond distances ranging from 2.38–2.43 Å. 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 CrSe4 tetrahedra, corners with two equivalent GaSe4 tetrahedra, corners with three FeSe4 tetrahedra, and edges with six GaSe6 octahedra. There are a spread of Ga–Se bond distances ranging from 2.63–2.67 Å. In the second 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 FeSe4 tetrahedra, and edges with six GaSe6 octahedra. There are a spread of Ga–Se bond distances ranging from 2.63–2.67 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 octahedral tilt angles are 57°. There are two shorter (2.45 Å) and two longer (2.46 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 two equivalent Cr3+ and one Ga3+ atom. In the second Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to one Cr3+ and two equivalent Ga3+ atoms. In the third Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to three Fe2+ atoms. In the fourth Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to three Fe2+ atoms. In the fifth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to four Ga3+ atoms. In the sixth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to one Cr3+ and three Ga3+ atoms. In the seventh Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to one Fe2+ and three Ga3+ atoms. In the eighth Se2- site, Se2- is bonded to one Fe2+ and three Ga3+ atoms to form distorted corner-sharing SeGa3Fe trigonal pyramids.