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Materials Data on RbAg3Se2 by Materials Project

RbAg3Se2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Rb1+ is bonded to seven Se2- atoms to form a mixture of distorted face and edge-sharing RbSe7 pentagonal bipyramids. There are a spread of Rb–Se bond distances ranging from 3.55–3.76 Å. There are three inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded in a distorted bent 120 degrees geometry to four Se2- atoms. There are a spread of Ag–Se bond distances ranging from 2.64–3.21 Å. In the second Ag1+ site, Ag1+ is bonded in a distorted trigonal planar geometry to three Se2- atoms. There are two shorter (2.70 Å) and one longer (2.76 Å) Ag–Se bond lengths. In the third Ag1+ site, Ag1+ is bonded in a distorted trigonal non-coplanar geometry to three Se2- atoms. There are one shorter (2.63 Å) and two longer (2.78 Å) Ag–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 8-coordinate geometry to four equivalent Rb1+ and four Ag1+ atoms. In the second Se2- site, Se2- is bonded in a 9-coordinate geometry to three equivalent Rb1+ and six Ag1+ atoms.

36 MATERIALS SCIENCE↗
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Materials Data on CsAg5Se3 by Materials Project

CsAg5Se3 crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. Cs1+ is bonded in a body-centered cubic geometry to eight Se2- atoms. All Cs–Se bond lengths are 3.82 Å. There are three inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded to four Se2- atoms to form distorted corner-sharing AgSe4 tetrahedra. There are two shorter (2.70 Å) and two longer (2.98 Å) Ag–Se bond lengths. In the second Ag1+ site, Ag1+ is bonded in a distorted trigonal planar geometry to three equivalent Se2- atoms. There are one shorter (2.67 Å) and two longer (2.80 Å) Ag–Se bond lengths. In the third Ag1+ site, Ag1+ is bonded in a 4-coordinate geometry to four Se2- atoms. There are a spread of Ag–Se bond distances ranging from 2.63–2.98 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 4-coordinate geometry to four equivalent Cs1+ and four Ag1+ atoms. In the second Se2- site, Se2- is bonded in a 9-coordinate geometry to two equivalent Cs1+ and seven Ag1+ atoms.

36 MATERIALS SCIENCE↗
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Materials Data on RbTa(CuSe2)2 by Materials Project

RbTa(CuSe2)2 crystallizes in the orthorhombic Ama2 space group. The structure is three-dimensional. Rb1+ is bonded in a 9-coordinate geometry to nine Se2- atoms. There are a spread of Rb–Se bond distances ranging from 3.58–3.95 Å. Ta5+ is bonded to four Se2- atoms to form TaSe4 tetrahedra that share edges with four CuSe4 tetrahedra. There are a spread of Ta–Se bond distances ranging from 2.42–2.47 Å. There are two inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with six CuSe4 tetrahedra and edges with two equivalent TaSe4 tetrahedra. There are two shorter (2.46 Å) and two longer (2.47 Å) Cu–Se bond lengths. In the second Cu1+ site, Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with four equivalent CuSe4 tetrahedra and edges with two equivalent TaSe4 tetrahedra. There are three shorter (2.46 Å) and one longer (2.47 Å) Cu–Se bond lengths. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 6-coordinate geometry to four equivalent Rb1+, one Ta5+, and one Cu1+ atom. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to one Rb1+, one Ta5+, and three Cu1+ atoms. In the third Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Rb1+, one Ta5+, and two Cu1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sm(ErSe2)3 by Materials Project

Er3SmSe6 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are three inequivalent Er3+ sites. In the first Er3+ site, Er3+ is bonded to six Se2- atoms to form ErSe6 octahedra that share corners with three equivalent ErSe6 octahedra, corners with two equivalent ErSe7 pentagonal bipyramids, and edges with four equivalent ErSe6 octahedra. The corner-sharing octahedra tilt angles range from 56–60°. There are a spread of Er–Se bond distances ranging from 2.77–2.88 Å. In the second Er3+ site, Er3+ is bonded to seven Se2- atoms to form distorted ErSe7 pentagonal bipyramids that share corners with three ErSe6 octahedra, edges with two equivalent ErSe6 octahedra, and edges with four equivalent ErSe7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 36–50°. There are a spread of Er–Se bond distances ranging from 2.81–3.05 Å. In the third Er3+ site, Er3+ is bonded to six Se2- atoms to form ErSe6 octahedra that share corners with three equivalent ErSe6 octahedra, a cornercorner with one ErSe7 pentagonal bipyramid, edges with four equivalent ErSe6 octahedra, and edges with two equivalent ErSe7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 56–60°. There are a spread of Er–Se bond distances ranging from 2.79–2.88 Å. Sm3+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Sm–Se bond distances ranging from 2.99–3.13 Å. There are six inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three Er3+ and one Sm3+ atom to form distorted SeSmEr3 trigonal pyramids that share corners with two equivalent SeSm2Er3 square pyramids, corners with four SeSm3Er2 trigonal bipyramids, corners with two equivalent SeSmEr3 trigonal pyramids, edges with three equivalent SeSm2Er3 square pyramids, and edges with two equivalent SeSm3Er2 trigonal bipyramids. In the second Se2- site, Se2- is bonded to three equivalent Er3+ and two equivalent Sm3+ atoms to form distorted SeSm2Er3 square pyramids that share corners with six SeSm2Er3 trigonal bipyramids, corners with two equivalent SeSmEr3 trigonal pyramids, edges with four equivalent SeSm2Er3 square pyramids, edges with two SeSm2Er3 trigonal bipyramids, and edges with three equivalent SeSmEr3 trigonal pyramids. In the third Se2- site, Se2- is bonded to two equivalent Er3+ and three equivalent Sm3+ atoms to form distorted SeSm3Er2 trigonal bipyramids that share corners with four equivalent SeSm2Er3 square pyramids, corners with two equivalent SeSm2Er3 trigonal bipyramids, a cornercorner with one SeSmEr3 trigonal pyramid, an edgeedge with one SeSm2Er3 square pyramid, edges with seven SeSm3Er2 trigonal bipyramids, and edges with two equivalent SeSmEr3 trigonal pyramids. In the fourth Se2- site, Se2- is bonded in a 4-coordinate geometry to four Er3+ atoms. In the fifth Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to four Er3+ atoms. In the sixth Se2- site, Se2- is bonded to three Er3+ and two equivalent Sm3+ atoms to form distorted SeSm2Er3 trigonal bipyramids that share corners with two equivalent SeSm2Er3 square pyramids, corners with two equivalent SeSm3Er2 trigonal bipyramids, corners with three equivalent SeSmEr3 trigonal pyramids, an edgeedge with one SeSm2Er3 square pyramid, and edges with five SeSm3Er2 trigonal bipyramids.

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Materials Data on K3GeSe3 by Materials Project

K3GeSe3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to six Se2- atoms to form a mixture of distorted corner, edge, and face-sharing KSe6 octahedra. The corner-sharing octahedral tilt angles are 39°. There are a spread of K–Se bond distances ranging from 3.36–3.70 Å. In the second K1+ site, K1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of K–Se bond distances ranging from 3.45–3.54 Å. In the third K1+ site, K1+ is bonded to six Se2- atoms to form a mixture of distorted corner, edge, and face-sharing KSe6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 33–68°. There are a spread of K–Se bond distances ranging from 3.29–3.54 Å. Ge3+ is bonded in a trigonal non-coplanar geometry to three Se2- atoms. There are two shorter (2.39 Å) and one longer (2.40 Å) Ge–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 7-coordinate geometry to six K1+ and one Ge3+ atom. In the second Se2- site, Se2- is bonded in a 7-coordinate geometry to six K1+ and one Ge3+ atom.

36 MATERIALS SCIENCE↗
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Materials Data on Sm4Si2Se3O7 by Materials Project

Sm4Si2Se3O7 crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. there are two inequivalent Sm3+ sites. In the first Sm3+ site, Sm3+ is bonded in a 9-coordinate geometry to three Se2- and six O2- atoms. There are one shorter (2.95 Å) and two longer (2.99 Å) Sm–Se bond lengths. There are four shorter (2.49 Å) and two longer (2.64 Å) Sm–O bond lengths. In the second Sm3+ site, Sm3+ is bonded in a 6-coordinate geometry to three Se2- and three O2- atoms. There are one shorter (2.95 Å) and two longer (2.97 Å) Sm–Se bond lengths. There are one shorter (2.36 Å) and two longer (2.48 Å) Sm–O bond lengths. Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is three shorter (1.65 Å) and one longer (1.66 Å) Si–O bond length. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 4-coordinate geometry to four equivalent Sm3+ and twelve O2- atoms. There are eight shorter (3.26 Å) and four longer (3.35 Å) Se–O bond lengths. In the second Se2- site, Se2- is bonded in a 6-coordinate geometry to four equivalent Sm3+ and two equivalent O2- atoms. Both Se–O bond lengths are 3.35 Å. In the third Se2- site, Se2- is bonded in a 4-coordinate geometry to four Sm3+ atoms. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent Si4+ and one Se2- atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three Sm3+, one Si4+, and one Se2- atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to three Sm3+, one Si4+, and one Se2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaSe by Materials Project

NaSe crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six equivalent Se1- atoms to form edge-sharing NaSe6 octahedra. All Na–Se bond lengths are 3.09 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six equivalent Se1- atoms. All Na–Se bond lengths are 3.00 Å. Se1- is bonded in a 7-coordinate geometry to six Na1+ and one Se1- atom. The Se–Se bond length is 2.48 Å.

36 MATERIALS SCIENCE↗
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Materials Data on Na2Sn2Se5 by Materials Project

Na2Sn2Se5 crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to seven Se2- atoms to form distorted NaSe7 pentagonal bipyramids that share corners with four equivalent NaSe7 pentagonal bipyramids, corners with three equivalent SnSe4 tetrahedra, edges with two equivalent NaSe6 octahedra, an edgeedge with one SnSe4 tetrahedra, and faces with two equivalent NaSe6 octahedra. There are a spread of Na–Se bond distances ranging from 3.10–3.45 Å. In the second Na1+ site, Na1+ is bonded to six Se2- atoms to form NaSe6 octahedra that share corners with four equivalent NaSe6 octahedra, corners with four equivalent SnSe4 tetrahedra, edges with two equivalent NaSe7 pentagonal bipyramids, and faces with two equivalent NaSe7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 15–27°. There are a spread of Na–Se bond distances ranging from 3.05–3.29 Å. There are two inequivalent Sn4+ sites. In the first Sn4+ site, Sn4+ is bonded to four Se2- atoms to form SnSe4 tetrahedra that share corners with four equivalent NaSe6 octahedra, corners with three equivalent NaSe7 pentagonal bipyramids, and an edgeedge with one NaSe7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 38–89°. There are a spread of Sn–Se bond distances ranging from 2.49–2.60 Å. In the second Sn4+ site, Sn4+ is bonded in a distorted rectangular see-saw-like geometry to four Se2- atoms. There are a spread of Sn–Se bond distances ranging from 2.50–2.61 Å. There are five inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 4-coordinate geometry to two Na1+ and two Sn4+ atoms. In the second Se2- site, Se2- is bonded to four Na1+ and one Sn4+ atom to form distorted SeNa4Sn trigonal bipyramids that share corners with four equivalent SeNa4Sn trigonal bipyramids, corners with three equivalent SeNa2Sn2 trigonal pyramids, and an edgeedge with one SeNa2Sn2 trigonal pyramid. In the third Se2- site, Se2- is bonded in a 5-coordinate geometry to four Na1+ and one Sn4+ atom. In the fourth Se2- site, Se2- is bonded in a 3-coordinate geometry to one Na1+ and two Sn4+ atoms. In the fifth Se2- site, Se2- is bonded to two Na1+ and two Sn4+ atoms to form a mixture of distorted edge and corner-sharing SeNa2Sn2 trigonal pyramids.

36 MATERIALS SCIENCE↗
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Materials Data on CsAg3Se2 by Materials Project

CsAg3Se2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Cs1+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Cs–Se bond distances ranging from 3.69–3.88 Å. There are three inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded in a distorted bent 120 degrees geometry to four Se2- atoms. There are a spread of Ag–Se bond distances ranging from 2.64–3.20 Å. In the second Ag1+ site, Ag1+ is bonded in a distorted trigonal planar geometry to three Se2- atoms. There are two shorter (2.70 Å) and one longer (2.75 Å) Ag–Se bond lengths. In the third Ag1+ site, Ag1+ is bonded in a distorted trigonal non-coplanar geometry to three Se2- atoms. There are one shorter (2.64 Å) and two longer (2.78 Å) Ag–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 8-coordinate geometry to four equivalent Cs1+ and four Ag1+ atoms. In the second Se2- site, Se2- is bonded in a 9-coordinate geometry to three equivalent Cs1+ and six Ag1+ atoms.

36 MATERIALS SCIENCE↗
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Materials Data on Rb2Cd3Se4 by Materials Project

Rb2Cd3Se4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Rb1+ sites. In the first Rb1+ site, Rb1+ is bonded to seven Se2- atoms to form distorted RbSe7 pentagonal bipyramids that share corners with two equivalent RbSe7 pentagonal bipyramids, corners with eleven CdSe4 tetrahedra, edges with two equivalent RbSe6 octahedra, edges with two equivalent RbSe7 pentagonal bipyramids, edges with five CdSe4 tetrahedra, and faces with two equivalent RbSe6 octahedra. There are a spread of Rb–Se bond distances ranging from 3.62–3.92 Å. In the second Rb1+ site, Rb1+ is bonded to six Se2- atoms to form distorted RbSe6 octahedra that share corners with ten CdSe4 tetrahedra, edges with two equivalent RbSe6 octahedra, edges with two equivalent RbSe7 pentagonal bipyramids, edges with four CdSe4 tetrahedra, and faces with two equivalent RbSe7 pentagonal bipyramids. There are a spread of Rb–Se bond distances ranging from 3.51–3.71 Å. There are two inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded to four Se2- atoms to form CdSe4 tetrahedra that share corners with four equivalent RbSe6 octahedra, corners with three equivalent RbSe7 pentagonal bipyramids, corners with four CdSe4 tetrahedra, an edgeedge with one RbSe6 octahedra, edges with two equivalent RbSe7 pentagonal bipyramids, and edges with two CdSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 8–92°. There are a spread of Cd–Se bond distances ranging from 2.66–2.81 Å. In the second Cd2+ site, Cd2+ is bonded to four Se2- atoms to form distorted CdSe4 tetrahedra that share corners with two equivalent RbSe6 octahedra, corners with five equivalent RbSe7 pentagonal bipyramids, corners with four equivalent CdSe4 tetrahedra, edges with two equivalent RbSe6 octahedra, an edgeedge with one RbSe7 pentagonal bipyramid, and edges with two equivalent CdSe4 tetrahedra. The corner-sharing octahedral tilt angles are 57°. There are a spread of Cd–Se bond distances ranging from 2.64–2.79 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 6-coordinate geometry to three Rb1+ and three Cd2+ atoms. In the second Se2- site, Se2- is bonded to three Rb1+ and three Cd2+ atoms to form a mixture of distorted edge and corner-sharing SeRb3Cd3 octahedra. The corner-sharing octahedra tilt angles range from 0–53°. In the third Se2- site, Se2- is bonded in a 7-coordinate geometry to four Rb1+ and three Cd2+ atoms.

36 MATERIALS SCIENCE↗
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Materials Data on RbEr2Cu3Se5 by Materials Project

RbEr2Cu3Se5 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Rb1+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Rb–Se bond distances ranging from 3.41–3.54 Å. Er3+ is bonded to six Se2- atoms to form ErSe6 octahedra that share a cornercorner with one ErSe6 octahedra, corners with four equivalent CuSe4 tetrahedra, edges with four equivalent ErSe6 octahedra, and edges with five CuSe4 tetrahedra. The corner-sharing octahedral tilt angles are 32°. There are a spread of Er–Se bond distances ranging from 2.80–2.92 Å. There are two inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with four equivalent ErSe6 octahedra, corners with four CuSe4 tetrahedra, edges with three equivalent ErSe6 octahedra, and an edgeedge with one CuSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 17–62°. There are a spread of Cu–Se bond distances ranging from 2.48–2.57 Å. In the second Cu1+ site, Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with six CuSe4 tetrahedra and edges with four equivalent ErSe6 octahedra. There are two shorter (2.41 Å) and two longer (2.69 Å) Cu–Se bond lengths. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 7-coordinate geometry to two equivalent Rb1+, two equivalent Er3+, and three Cu1+ atoms. In the second Se2- site, Se2- is bonded in a 6-coordinate geometry to two equivalent Rb1+, two equivalent Er3+, and two equivalent Cu1+ atoms. In the third Se2- site, Se2- is bonded to one Rb1+, three equivalent Er3+, and two equivalent Cu1+ atoms to form a mixture of distorted edge and corner-sharing SeRbEr3Cu2 octahedra. The corner-sharing octahedral tilt angles are 54°.

36 MATERIALS SCIENCE↗
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Materials Data on NaAlSe2 by Materials Project

NaAlSe2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six Se2- atoms to form distorted NaSe6 pentagonal pyramids that share corners with ten AlSe4 tetrahedra, edges with two equivalent NaSe6 pentagonal pyramids, an edgeedge with one AlSe4 tetrahedra, and faces with three NaSe6 pentagonal pyramids. There are a spread of Na–Se bond distances ranging from 3.02–3.21 Å. In the second Na1+ site, Na1+ is bonded to six Se2- atoms to form distorted NaSe6 pentagonal pyramids that share corners with four equivalent NaSe6 pentagonal pyramids, corners with six AlSe4 tetrahedra, edges with two equivalent NaSe6 pentagonal pyramids, edges with three AlSe4 tetrahedra, and faces with two equivalent NaSe6 pentagonal pyramids. There are a spread of Na–Se bond distances ranging from 3.10–3.22 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four Se2- atoms to form AlSe4 tetrahedra that share corners with eight NaSe6 pentagonal pyramids, corners with four AlSe4 tetrahedra, and edges with two NaSe6 pentagonal pyramids. There are one shorter (2.40 Å) and three longer (2.41 Å) Al–Se bond lengths. In the second Al3+ site, Al3+ is bonded to four Se2- atoms to form AlSe4 tetrahedra that share corners with eight NaSe6 pentagonal pyramids, corners with four AlSe4 tetrahedra, and edges with two equivalent NaSe6 pentagonal pyramids. There are one shorter (2.40 Å) and three longer (2.41 Å) Al–Se bond lengths. There are five inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 2-coordinate geometry to four Na1+ and two equivalent Al3+ atoms. In the second Se2- site, Se2- is bonded in a 2-coordinate geometry to four Na1+ and two equivalent Al3+ atoms. In the third Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to two Na1+ and two Al3+ atoms. In the fourth Se2- site, Se2- is bonded in a 2-coordinate geometry to four Na1+ and two Al3+ atoms. In the fifth Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to two Na1+ and two Al3+ atoms.

36 MATERIALS SCIENCE↗
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Materials Data on Na3GaSe3 by Materials Project

Na3GaSe3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of Na–Se bond distances ranging from 2.96–3.60 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of Na–Se bond distances ranging from 2.92–3.49 Å. In the third Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of Na–Se bond distances ranging from 2.99–3.64 Å. Ga3+ is bonded to four Se2- atoms to form edge-sharing GaSe4 tetrahedra. There are a spread of Ga–Se bond distances ranging from 2.40–2.50 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to six Na1+ and two equivalent Ga3+ atoms. In the second Se2- site, Se2- is bonded in a 7-coordinate geometry to six Na1+ and one Ga3+ atom. In the third Se2- site, Se2- is bonded in a 7-coordinate geometry to six Na1+ and one Ga3+ atom.

36 MATERIALS SCIENCE↗
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Materials Data on BaCu2GeSe4 by Materials Project

BaCu2GeSe4 crystallizes in the trigonal P3_1 space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Ba–Se bond distances ranging from 3.35–3.42 Å. There are two inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with four equivalent CuSe4 tetrahedra and corners with four equivalent GeSe4 tetrahedra. There are a spread of Cu–Se bond distances ranging from 2.45–2.52 Å. In the second Cu1+ site, Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with four equivalent CuSe4 tetrahedra and corners with four equivalent GeSe4 tetrahedra. There are a spread of Cu–Se bond distances ranging from 2.45–2.52 Å. Ge4+ is bonded to four Se2- atoms to form GeSe4 tetrahedra that share corners with eight CuSe4 tetrahedra. There are three shorter (2.42 Å) and one longer (2.43 Å) Ge–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to two equivalent Ba2+, two Cu1+, and one Ge4+ atom. In the second Se2- site, Se2- is bonded to two equivalent Ba2+, two Cu1+, and one Ge4+ atom to form a mixture of distorted corner and edge-sharing SeBa2Cu2Ge trigonal bipyramids. In the third Se2- site, Se2- is bonded to two equivalent Ba2+, two Cu1+, and one Ge4+ atom to form a mixture of distorted corner and edge-sharing SeBa2Cu2Ge trigonal bipyramids. In the fourth Se2- site, Se2- is bonded in a 5-coordinate geometry to two equivalent Ba2+, two Cu1+, and one Ge4+ atom.

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Materials Data on TlGaSe2 by Materials Project

TlGaSe2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Tl1+ sites. In the first Tl1+ site, Tl1+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Tl–Se bond distances ranging from 3.28–3.69 Å. In the second Tl1+ site, Tl1+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Tl–Se bond distances ranging from 3.30–3.79 Å. There are two inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four Se2- atoms to form corner-sharing GaSe4 tetrahedra. There are three shorter (2.45 Å) and one longer (2.46 Å) Ga–Se bond lengths. In the second Ga3+ site, Ga3+ is bonded to four Se2- atoms to form corner-sharing GaSe4 tetrahedra. There are a spread of Ga–Se bond distances ranging from 2.43–2.46 Å. There are five inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 2-coordinate geometry to four Tl1+ and two Ga3+ atoms. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to three Tl1+ and two Ga3+ atoms. In the third Se2- site, Se2- is bonded in a 2-coordinate geometry to four Tl1+ and two equivalent Ga3+ atoms. In the fourth Se2- site, Se2- is bonded in a 2-coordinate geometry to four Tl1+ and two equivalent Ga3+ atoms. In the fifth Se2- site, Se2- is bonded in a 5-coordinate geometry to three Tl1+ and two Ga3+ atoms.

36 MATERIALS SCIENCE↗
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Materials Data on K2Hg3(GeSe4)2 by Materials Project

K2Hg3Ge2Se8 crystallizes in the orthorhombic Aea2 space group. The structure is three-dimensional. K1+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of K–Se bond distances ranging from 3.37–3.98 Å. There are two inequivalent Hg2+ sites. In the first Hg2+ site, Hg2+ is bonded in a see-saw-like geometry to four Se2- atoms. There are a spread of Hg–Se bond distances ranging from 2.60–3.01 Å. In the second Hg2+ site, Hg2+ is bonded in a distorted linear geometry to four Se2- atoms. There are two shorter (2.51 Å) and two longer (3.42 Å) Hg–Se bond lengths. Ge4+ is bonded in a tetrahedral geometry to four Se2- atoms. There are a spread of Ge–Se bond distances ranging from 2.35–2.43 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to two equivalent K1+, two Hg2+, and one Ge4+ atom. In the second Se2- site, Se2- is bonded in a 2-coordinate geometry to two equivalent K1+, one Hg2+, and one Ge4+ atom. In the third Se2- site, Se2- is bonded in a 4-coordinate geometry to two equivalent K1+, one Hg2+, and one Ge4+ atom. In the fourth Se2- site, Se2- is bonded in a 4-coordinate geometry to two equivalent K1+, two equivalent Hg2+, and one Ge4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsEr3Se5 by Materials Project

CsEr3Se5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Cs1+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Cs–Se bond distances ranging from 3.69–3.89 Å. There are three inequivalent Er3+ sites. In the first Er3+ site, Er3+ is bonded to six Se2- atoms to form a mixture of corner and edge-sharing ErSe6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are a spread of Er–Se bond distances ranging from 2.80–2.97 Å. In the second Er3+ site, Er3+ is bonded to six Se2- atoms to form a mixture of corner and edge-sharing ErSe6 octahedra. The corner-sharing octahedra tilt angles range from 1–12°. There are a spread of Er–Se bond distances ranging from 2.79–2.96 Å. In the third Er3+ site, Er3+ is bonded to six Se2- atoms to form a mixture of corner and edge-sharing ErSe6 octahedra. The corner-sharing octahedral tilt angles are 12°. There are a spread of Er–Se bond distances ranging from 2.81–2.90 Å. There are five inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to two equivalent Cs1+ and three Er3+ atoms. In the second Se2- site, Se2- is bonded in a 4-coordinate geometry to one Cs1+ and four Er3+ atoms. In the third Se2- site, Se2- is bonded in a 5-coordinate geometry to two equivalent Cs1+ and three Er3+ atoms. In the fourth Se2- site, Se2- is bonded in a 5-coordinate geometry to two equivalent Cs1+ and three Er3+ atoms. In the fifth Se2- site, Se2- is bonded to five Er3+ atoms to form edge-sharing SeEr5 square pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K3SbSe3 by Materials Project

K3SbSe3 crystallizes in the cubic P2_13 space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to six equivalent Se2- atoms to form a mixture of distorted corner, edge, and face-sharing KSe6 octahedra. The corner-sharing octahedra tilt angles range from 30–44°. There are three shorter (3.31 Å) and three longer (3.50 Å) K–Se bond lengths. In the second K1+ site, K1+ is bonded to six equivalent Se2- atoms to form a mixture of distorted corner, edge, and face-sharing KSe6 octahedra. The corner-sharing octahedra tilt angles range from 30–42°. There are three shorter (3.33 Å) and three longer (3.48 Å) K–Se bond lengths. In the third K1+ site, K1+ is bonded to six equivalent Se2- atoms to form a mixture of corner, edge, and face-sharing KSe6 octahedra. The corner-sharing octahedra tilt angles range from 35–60°. There are three shorter (3.57 Å) and three longer (3.67 Å) K–Se bond lengths. Sb3+ is bonded in a trigonal non-coplanar geometry to three equivalent Se2- atoms. All Sb–Se bond lengths are 2.60 Å. Se2- is bonded to six K1+ and one Sb3+ atom to form a mixture of distorted corner, edge, and face-sharing SeK6Sb pentagonal bipyramids.

36 MATERIALS SCIENCE↗