Materials Data on Sm9Ga5Se21 by Materials Project
Sm9Ga5Se21 crystallizes in the trigonal R3 space group. The structure is three-dimensional. there are six inequivalent Sm3+ sites. In the first Sm3+ site, Sm3+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Sm–Se bond distances ranging from 2.96–3.13 Å. In the second Sm3+ site, Sm3+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Sm–Se bond distances ranging from 2.93–3.38 Å. In the third Sm3+ site, Sm3+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Sm–Se bond distances ranging from 2.93–3.17 Å. In the fourth Sm3+ site, Sm3+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Sm–Se bond distances ranging from 2.93–3.17 Å. In the fifth Sm3+ site, Sm3+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Sm–Se bond distances ranging from 2.94–3.36 Å. In the sixth Sm3+ site, Sm3+ is bonded to seven Se2- atoms to form distorted SmSe7 pentagonal bipyramids that share a cornercorner with one GaSe6 octahedra, corners with two equivalent SmSe7 pentagonal bipyramids, corners with two GaSe4 tetrahedra, and an edgeedge with one GaSe4 tetrahedra. The corner-sharing octahedral tilt angles are 40°. There are a spread of Sm–Se bond distances ranging from 2.94–3.20 Å. There are six inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four Se2- atoms to form GaSe4 tetrahedra that share a cornercorner with one SmSe7 pentagonal bipyramid. There are a spread of Ga–Se bond distances ranging from 2.38–2.44 Å. In the second Ga3+ site, Ga3+ is bonded to four Se2- atoms to form GaSe4 tetrahedra that share a cornercorner with one SmSe7 pentagonal bipyramid and an edgeedge with one SmSe7 pentagonal bipyramid. There are a spread of Ga–Se bond distances ranging from 2.39–2.44 Å. In the third Ga3+ site, Ga3+ is bonded to six Se2- atoms to form GaSe6 octahedra that share corners with three equivalent SmSe7 pentagonal bipyramids. There are three shorter (2.64 Å) and three longer (2.69 Å) Ga–Se bond lengths. In the fourth Ga3+ site, Ga3+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are three shorter (2.44 Å) and three longer (3.06 Å) Ga–Se bond lengths. In the fifth Ga3+ site, Ga3+ is bonded in a 3-coordinate geometry to six Se2- atoms. There are three shorter (2.44 Å) and three longer (3.09 Å) Ga–Se bond lengths. In the sixth Ga3+ site, Ga3+ is bonded in an octahedral geometry to six Se2- atoms. There are three shorter (2.65 Å) and three longer (2.68 Å) Ga–Se bond lengths. There are fourteen inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to four Sm3+ and one Ga3+ atom. In the second Se2- site, Se2- is bonded to three Sm3+ and two Ga3+ atoms to form distorted SeSm3Ga2 square pyramids that share corners with three SeSm3Ga tetrahedra, a cornercorner with one SeSm3Ga trigonal pyramid, edges with two equivalent SeSm3Ga trigonal pyramids, and faces with two equivalent SeSm3Ga2 square pyramids. In the third Se2- site, Se2- is bonded to three Sm3+ and one Ga3+ atom to form distorted SeSm3Ga trigonal pyramids that share a cornercorner with one SeSm3Ga2 square pyramid, corners with three SeSm3Ga tetrahedra, edges with two equivalent SeSm3Ga2 square pyramids, and edges with two equivalent SeSm3Ga trigonal pyramids. In the fourth Se2- site, Se2- is bonded to three Sm3+ and two Ga3+ atoms to form distorted SeSm3Ga2 square pyramids that share corners with three SeSm3Ga tetrahedra, a cornercorner with one SeSm3Ga trigonal pyramid, edges with two equivalent SeSm3Ga trigonal pyramids, and faces with two equivalent SeSm3Ga2 square pyramids. In the fifth Se2- site, Se2- is bonded to three Sm3+ and one Ga3+ atom to form distorted SeSm3Ga trigonal pyramids that share a cornercorner with one SeSm3Ga2 square pyramid, corners with three SeSm3Ga tetrahedra, edges with two equivalent SeSm3Ga2 square pyramids, and edges with two equivalent SeSm3Ga trigonal pyramids. In the sixth Se2- site, Se2- is bonded in a 5-coordinate geometry to four Sm3+ and one Ga3+ atom. In the seventh Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Sm3+ and one Ga3+ atom. In the eighth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Sm3+ and one Ga3+ atom. In the ninth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Sm3+ and one Ga3+ atom. In the tenth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Sm3+ and one Ga3+ atom. In the eleventh Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Sm3+ and one Ga3+ atom. In the twelfth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Sm3+ and one Ga3+ atom. In the thirteenth Se2- site, Se2- is bonded to three Sm3+ and one Ga3+ atom to form distorted SeSm3Ga tetrahedra that share corners with three SeSm3Ga2 square pyramids and corners with three SeSm3Ga trigonal pyramids. In the fourteenth Se2- site, Se2- is bonded to three Sm3+ and one Ga3+ atom to form distorted SeSm3Ga tetrahedra that share corners with three SeSm3Ga2 square pyramids and corners with three SeSm3Ga trigonal pyramids.