Materials Data on Cr4(Ga2Se5)3 by Materials Project
Cr4(Ga2Se5)3 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are three inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with four GaSe4 tetrahedra and edges with six equivalent CrSe6 octahedra. There are five shorter (2.57 Å) and one longer (2.58 Å) Cr–Se bond lengths. In the second Cr3+ site, Cr3+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with four GaSe4 tetrahedra and edges with six CrSe6 octahedra. There are a spread of Cr–Se bond distances ranging from 2.48–2.62 Å. In the third Cr3+ site, Cr3+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with four GaSe4 tetrahedra and edges with four GaSe4 tetrahedra. There are a spread of Cr–Se bond distances ranging from 2.60–2.66 Å. There are three inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four Se2- atoms to form GaSe4 tetrahedra that share corners with three CrSe6 octahedra and corners with five GaSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 58–62°. There are a spread of Ga–Se bond distances ranging from 2.34–2.47 Å. In the second Ga3+ site, Ga3+ is bonded to four Se2- atoms to form GaSe4 tetrahedra that share corners with four CrSe6 octahedra, corners with three equivalent GaSe4 tetrahedra, and an edgeedge with one CrSe6 octahedra. The corner-sharing octahedra tilt angles range from 20–61°. There are a spread of Ga–Se bond distances ranging from 2.39–2.49 Å. In the third Ga3+ site, Ga3+ is bonded to four Se2- atoms to form GaSe4 tetrahedra that share a cornercorner with one CrSe6 octahedra, corners with five GaSe4 tetrahedra, and an edgeedge with one CrSe6 octahedra. The corner-sharing octahedral tilt angles are 20°. There are a spread of Ga–Se bond distances ranging from 2.39–2.49 Å. There are ten inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to one Cr3+ and two equivalent Ga3+ atoms. In the second Se2- site, Se2- is bonded in a distorted T-shaped geometry to three Cr3+ atoms. In the third Se2- site, Se2- is bonded in a distorted T-shaped geometry to one Cr3+ and two equivalent Ga3+ atoms. In the fourth Se2- site, Se2- is bonded to three Cr3+ and one Ga3+ atom to form a mixture of distorted corner and edge-sharing SeCr3Ga tetrahedra. In the fifth Se2- site, Se2- is bonded in a distorted T-shaped geometry to three Cr3+ atoms. In the sixth Se2- site, Se2- is bonded in a water-like geometry to two equivalent Ga3+ atoms. In the seventh Se2- site, Se2- is bonded in a distorted T-shaped geometry to one Cr3+ and two equivalent Ga3+ atoms. In the eighth Se2- site, Se2- is bonded in a 3-coordinate geometry to one Cr3+ and two equivalent Ga3+ atoms. In the ninth Se2- site, Se2- is bonded to three Cr3+ and one Ga3+ atom to form a mixture of distorted corner and edge-sharing SeCr3Ga tetrahedra. In the tenth Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to three Ga3+ atoms.