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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on CsBiS2 by Materials Project

CsBiS2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Cs1+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Cs–S bond distances ranging from 3.60–3.99 Å. Bi3+ is bonded in a distorted rectangular see-saw-like geometry to five S2- atoms. There are a spread of Bi–S bond distances ranging from 2.57–3.57 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded to four equivalent Cs1+ and two equivalent Bi3+ atoms to form a mixture of distorted edge, face, and corner-sharing SCs4Bi2 octahedra. The corner-sharing octahedra tilt angles range from 39–41°. In the second S2- site, S2- is bonded in a 6-coordinate geometry to three equivalent Cs1+ and three equivalent Bi3+ atoms.

36 MATERIALS SCIENCE↗
NASA NTRS1979

On volatile element trends in gas-rich meteorites

Study of 10 volatile elements (and non-volatile Co) in co-existing light and dark portions of 6 gas-rich chondrites indicates patterns of distinct but non-uniform enrichment of volatile elements. Only Cs is enriched in all samples; Bi and Tl enrichments covary. The observed enrichments are inconsistent with prior suggestions of admixture of C1 or C2 chondritic matter, whether pristine or partly devolatilized, but suggest that both light and dark portions of each chondrite represents a compositionally more extended sampling of parental nebular material than hitherto known.

Bart, G.↗
DOE OSTI2020

Materials Data on Cs3Cu2(BiS2)5 by Materials Project

Cs3Bi5Cu2S10 crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 6-coordinate geometry to six S2- atoms. There are four shorter (3.44 Å) and two longer (3.46 Å) Cs–S bond lengths. In the second Cs1+ site, Cs1+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Cs–S bond distances ranging from 3.48–3.80 Å. Cu1+ is bonded to four S2- atoms to form CuS4 tetrahedra that share a cornercorner with one BiS6 octahedra, corners with two equivalent CuS4 tetrahedra, and edges with four BiS6 octahedra. The corner-sharing octahedral tilt angles are 13°. There are a spread of Cu–S bond distances ranging from 2.34–2.69 Å. There are three inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded to six S2- atoms to form BiS6 octahedra that share a cornercorner with one BiS6 octahedra, edges with six BiS6 octahedra, and edges with two equivalent CuS4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. There are a spread of Bi–S bond distances ranging from 2.68–3.08 Å. In the second Bi3+ site, Bi3+ is bonded to six S2- atoms to form distorted BiS6 octahedra that share corners with three BiS6 octahedra, edges with five BiS6 octahedra, and edges with two equivalent CuS4 tetrahedra. The corner-sharing octahedra tilt angles range from 8–41°. There are a spread of Bi–S bond distances ranging from 2.65–3.24 Å. In the third Bi3+ site, Bi3+ is bonded to six S2- atoms to form BiS6 octahedra that share corners with four equivalent BiS6 octahedra, corners with two equivalent CuS4 tetrahedra, and edges with eight BiS6 octahedra. The corner-sharing octahedral tilt angles are 8°. There are two shorter (2.85 Å) and four longer (2.90 Å) Bi–S bond lengths. There are five inequivalent S2- sites. In the first S2- site, S2- is bonded to three Cs1+, one Cu1+, and two equivalent Bi3+ atoms to form distorted SCs3CuBi2 octahedra that share corners with seven SCs3CuBi2 octahedra, corners with two equivalent SCs2Bi3 square pyramids, edges with three SCs3CuBi2 octahedra, edges with two equivalent SCs2Bi3 square pyramids, and a faceface with one SCs2CuBi3 octahedra. The corner-sharing octahedra tilt angles range from 0–74°. In the second S2- site, S2- is bonded to two equivalent Cs1+, one Cu1+, and three Bi3+ atoms to form distorted SCs2CuBi3 octahedra that share corners with three SCs3CuBi2 octahedra, corners with two equivalent SCs2Bi3 square pyramids, edges with six SCs2CuBi3 octahedra, an edgeedge with one SCs2Bi3 square pyramid, and a faceface with one SCs3CuBi2 octahedra. The corner-sharing octahedra tilt angles range from 0–74°. In the third S2- site, S2- is bonded to one Cs1+ and five Bi3+ atoms to form SCsBi5 octahedra that share corners with six SCs3CuBi2 octahedra, edges with eight SCs3CuBi2 octahedra, and edges with two equivalent SCs2Bi3 square pyramids. The corner-sharing octahedra tilt angles range from 0–46°. In the fourth S2- site, S2- is bonded to two equivalent Cs1+ and three Bi3+ atoms to form SCs2Bi3 square pyramids that share corners with four SCs3CuBi2 octahedra, corners with two equivalent SCs2Bi3 square pyramids, edges with five SCs3CuBi2 octahedra, and edges with three equivalent SCs2Bi3 square pyramids. The corner-sharing octahedra tilt angles range from 6–69°. In the fifth S2- site, S2- is bonded in a 6-coordinate geometry to two equivalent Cs1+, two equivalent Cu1+, and two Bi3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsK2BiCl6 by Materials Project

CsK2BiCl6 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Cs1+ is bonded in a 10-coordinate geometry to ten Cl1- atoms. There are a spread of Cs–Cl bond distances ranging from 3.58–4.00 Å. There are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 7-coordinate geometry to seven Cl1- atoms. There are a spread of K–Cl bond distances ranging from 3.12–3.52 Å. In the second K1+ site, K1+ is bonded in a 8-coordinate geometry to eight Cl1- atoms. There are a spread of K–Cl bond distances ranging from 3.15–3.87 Å. There are two inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded in an octahedral geometry to six Cl1- atoms. There are a spread of Bi–Cl bond distances ranging from 2.72–2.77 Å. In the second Bi3+ site, Bi3+ is bonded in an octahedral geometry to six Cl1- atoms. There are a spread of Bi–Cl bond distances ranging from 2.71–2.75 Å. There are six inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded to four K1+ and one Bi3+ atom to form distorted ClK4Bi trigonal bipyramids that share corners with two equivalent ClCs2K2Bi square pyramids, a cornercorner with one ClK4Bi trigonal bipyramid, corners with four equivalent ClCsK2Bi trigonal pyramids, an edgeedge with one ClCs2K2Bi square pyramid, edges with two equivalent ClK4Bi trigonal bipyramids, and an edgeedge with one ClCsK2Bi trigonal pyramid. In the second Cl1- site, Cl1- is bonded in a 6-coordinate geometry to three equivalent Cs1+, two K1+, and one Bi3+ atom. In the third Cl1- site, Cl1- is bonded in a 4-coordinate geometry to one Cs1+, three K1+, and one Bi3+ atom. In the fourth Cl1- site, Cl1- is bonded to one Cs1+, two K1+, and one Bi3+ atom to form distorted ClCsK2Bi trigonal pyramids that share corners with four equivalent ClCs2K2Bi square pyramids, corners with four equivalent ClK4Bi trigonal bipyramids, a cornercorner with one ClCsK2Bi trigonal pyramid, and an edgeedge with one ClK4Bi trigonal bipyramid. In the fifth Cl1- site, Cl1- is bonded to two equivalent Cs1+, two K1+, and one Bi3+ atom to form distorted ClCs2K2Bi square pyramids that share corners with two equivalent ClK4Bi trigonal bipyramids, corners with four equivalent ClCsK2Bi trigonal pyramids, an edgeedge with one ClK4Bi trigonal bipyramid, and a faceface with one ClCs2K2Bi square pyramid. In the sixth Cl1- site, Cl1- is bonded in a 6-coordinate geometry to three equivalent Cs1+, two K1+, and one Bi3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsCu(BiS2)2 by Materials Project

CsBi2CuS4 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. Cs1+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Cs–S bond distances ranging from 3.47–3.77 Å. Cu1+ is bonded to four S2- atoms to form CuS4 tetrahedra that share corners with two BiS6 octahedra, corners with two equivalent CuS4 tetrahedra, and edges with four BiS6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are a spread of Cu–S bond distances ranging from 2.28–2.72 Å. There are two inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded to six S2- atoms to form BiS6 octahedra that share corners with three equivalent BiS6 octahedra, a cornercorner with one CuS4 tetrahedra, edges with five BiS6 octahedra, and edges with two equivalent CuS4 tetrahedra. The corner-sharing octahedra tilt angles range from 3–25°. There are a spread of Bi–S bond distances ranging from 2.67–3.12 Å. In the second Bi3+ site, Bi3+ is bonded to six S2- atoms to form distorted BiS6 octahedra that share corners with three equivalent BiS6 octahedra, a cornercorner with one CuS4 tetrahedra, edges with five BiS6 octahedra, and edges with two equivalent CuS4 tetrahedra. The corner-sharing octahedra tilt angles range from 3–25°. There are a spread of Bi–S bond distances ranging from 2.67–3.27 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to one Cs1+ and four Bi3+ atoms to form distorted SCsBi4 square pyramids that share corners with eight SCs2CuBi3 octahedra, edges with four SCs2CuBi3 octahedra, and edges with two equivalent SCsBi4 square pyramids. The corner-sharing octahedra tilt angles range from 2–81°. In the second S2- site, S2- is bonded to two equivalent Cs1+, one Cu1+, and three Bi3+ atoms to form distorted SCs2CuBi3 octahedra that share corners with two equivalent SCs2CuBi3 octahedra, corners with six equivalent SCsBi4 square pyramids, edges with four SCs2CuBi3 octahedra, an edgeedge with one SCsBi4 square pyramid, and a faceface with one SCs2CuBi3 octahedra. The corner-sharing octahedral tilt angles are 68°. In the third S2- site, S2- is bonded to two equivalent Cs1+, one Cu1+, and three Bi3+ atoms to form distorted SCs2CuBi3 octahedra that share corners with two equivalent SCs2CuBi3 octahedra, corners with two equivalent SCsBi4 square pyramids, edges with four SCs2CuBi3 octahedra, edges with three equivalent SCsBi4 square pyramids, and a faceface with one SCs2CuBi3 octahedra. The corner-sharing octahedral tilt angles are 68°. In the fourth S2- site, S2- is bonded in a 6-coordinate geometry to two equivalent Cs1+, two equivalent Cu1+, and two Bi3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs2MnBi2S5 by Materials Project

Cs2Bi2MnS5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Cs–S bond distances ranging from 3.54–3.62 Å. In the second Cs1+ site, Cs1+ is bonded to six S2- atoms to form distorted CsS6 octahedra that share corners with five BiS6 octahedra, corners with three equivalent MnS4 tetrahedra, edges with four equivalent CsS6 octahedra, edges with five BiS6 octahedra, and an edgeedge with one MnS4 tetrahedra. The corner-sharing octahedra tilt angles range from 1–59°. There are a spread of Cs–S bond distances ranging from 3.48–3.65 Å. Mn2+ is bonded to four S2- atoms to form MnS4 tetrahedra that share corners with three equivalent CsS6 octahedra, corners with two equivalent MnS4 tetrahedra, an edgeedge with one CsS6 octahedra, and edges with four BiS6 octahedra. The corner-sharing octahedra tilt angles range from 1–27°. There are a spread of Mn–S bond distances ranging from 2.40–2.46 Å. There are two inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded to six S2- atoms to form BiS6 octahedra that share a cornercorner with one BiS6 octahedra, corners with two equivalent CsS6 octahedra, edges with three equivalent CsS6 octahedra, edges with four BiS6 octahedra, and edges with two equivalent MnS4 tetrahedra. The corner-sharing octahedra tilt angles range from 11–36°. There are a spread of Bi–S bond distances ranging from 2.66–3.25 Å. In the second Bi3+ site, Bi3+ is bonded to six S2- atoms to form BiS6 octahedra that share a cornercorner with one BiS6 octahedra, corners with three equivalent CsS6 octahedra, edges with two equivalent CsS6 octahedra, edges with four BiS6 octahedra, and edges with two equivalent MnS4 tetrahedra. The corner-sharing octahedra tilt angles range from 1–59°. There are a spread of Bi–S bond distances ranging from 2.78–2.98 Å. There are five inequivalent S2- sites. In the first S2- site, S2- is bonded to three Cs1+, one Mn2+, and two equivalent Bi3+ atoms to form distorted SCs3MnBi2 octahedra that share a cornercorner with one SCs3Bi3 octahedra, corners with four equivalent SCs2Bi3 square pyramids, edges with four SCs3MnBi2 octahedra, and edges with two equivalent SCs2Bi3 square pyramids. The corner-sharing octahedral tilt angles are 16°. In the second S2- site, S2- is bonded to three equivalent Cs1+ and three Bi3+ atoms to form SCs3Bi3 octahedra that share a cornercorner with one SCs3MnBi2 octahedra, edges with six SCs3MnBi2 octahedra, and edges with two equivalent SCs2Bi3 square pyramids. The corner-sharing octahedral tilt angles are 16°. In the third S2- site, S2- is bonded in a 2-coordinate geometry to two equivalent Cs1+, two equivalent Mn2+, and two Bi3+ atoms. In the fourth S2- site, S2- is bonded to two equivalent Cs1+ and three Bi3+ atoms to form distorted SCs2Bi3 square pyramids that share corners with four equivalent SCs3MnBi2 octahedra, edges with four SCs3MnBi2 octahedra, and edges with two equivalent SCs2Bi3 square pyramids. The corner-sharing octahedra tilt angles range from 4–47°. In the fifth S2- site, S2- is bonded in a 6-coordinate geometry to three equivalent Cs1+, one Mn2+, and two equivalent Bi3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsNb2BiO7 by Materials Project

CsBiNb2O7 crystallizes in the orthorhombic Pmc2_1 space group. The structure is three-dimensional. Cs1+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. There are a spread of Cs–O bond distances ranging from 3.10–3.30 Å. Nb5+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Nb–O bond distances ranging from 1.80–2.45 Å. Bi3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Bi–O bond distances ranging from 2.22–2.81 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Nb5+ and one Bi3+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Nb5+ and two equivalent Bi3+ atoms. In the third O2- site, O2- is bonded in a distorted single-bond geometry to four equivalent Cs1+ and one Nb5+ atom. In the fourth O2- site, O2- is bonded in a distorted see-saw-like geometry to two equivalent Nb5+ and two equivalent Bi3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs(Bi2Te3)2 by Materials Project

CsBi4Te6 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 10-coordinate geometry to ten Te2- atoms. There are a spread of Cs–Te bond distances ranging from 3.88–4.29 Å. In the second Cs1+ site, Cs1+ is bonded in a 9-coordinate geometry to nine Te2- atoms. There are a spread of Cs–Te bond distances ranging from 3.80–4.21 Å. There are eight inequivalent Bi+2.75+ sites. In the first Bi+2.75+ site, Bi+2.75+ is bonded to six Te2- atoms to form BiTe6 octahedra that share corners with three BiTe6 octahedra, a cornercorner with one BiTe5 square pyramid, and edges with seven BiTe6 octahedra. The corner-sharing octahedral tilt angles are 7°. There are a spread of Bi–Te bond distances ranging from 3.03–3.45 Å. In the second Bi+2.75+ site, Bi+2.75+ is bonded to six Te2- atoms to form a mixture of corner and edge-sharing BiTe6 octahedra. The corner-sharing octahedra tilt angles range from 2–7°. There are a spread of Bi–Te bond distances ranging from 3.14–3.27 Å. In the third Bi+2.75+ site, Bi+2.75+ is bonded to six Te2- atoms to form BiTe6 octahedra that share corners with three BiTe6 octahedra, a cornercorner with one BiTe5 square pyramid, and edges with eleven BiTe6 octahedra. The corner-sharing octahedral tilt angles are 7°. There are a spread of Bi–Te bond distances ranging from 3.09–3.32 Å. In the fourth Bi+2.75+ site, Bi+2.75+ is bonded to six Te2- atoms to form BiTe6 octahedra that share corners with three BiTe6 octahedra, edges with seven BiTe6 octahedra, and edges with four BiTe5 square pyramids. The corner-sharing octahedra tilt angles range from 2–7°. There are a spread of Bi–Te bond distances ranging from 3.04–3.44 Å. In the fifth Bi+2.75+ site, Bi+2.75+ is bonded to six Te2- atoms to form a mixture of corner and edge-sharing BiTe6 octahedra. The corner-sharing octahedra tilt angles range from 5–15°. There are a spread of Bi–Te bond distances ranging from 3.04–3.45 Å. In the sixth Bi+2.75+ site, Bi+2.75+ is bonded to six Te2- atoms to form BiTe6 octahedra that share corners with three BiTe6 octahedra, edges with five BiTe6 octahedra, and edges with two equivalent BiTe5 square pyramids. The corner-sharing octahedra tilt angles range from 7–15°. There are a spread of Bi–Te bond distances ranging from 3.00–3.40 Å. In the seventh Bi+2.75+ site, Bi+2.75+ is bonded to five Te2- atoms to form BiTe5 square pyramids that share a cornercorner with one BiTe6 octahedra, corners with two equivalent BiTe5 square pyramids, edges with two equivalent BiTe6 octahedra, and edges with three BiTe5 square pyramids. The corner-sharing octahedral tilt angles are 10°. There are a spread of Bi–Te bond distances ranging from 3.06–3.45 Å. In the eighth Bi+2.75+ site, Bi+2.75+ is bonded to five Te2- atoms to form BiTe5 square pyramids that share a cornercorner with one BiTe6 octahedra, corners with two equivalent BiTe5 square pyramids, edges with four BiTe6 octahedra, and edges with three BiTe5 square pyramids. The corner-sharing octahedral tilt angles are 6°. There are a spread of Bi–Te bond distances ranging from 3.09–3.55 Å. There are twelve inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to six Bi+2.75+ atoms to form TeBi6 octahedra that share a cornercorner with one TeBi6 octahedra, corners with two equivalent TeCsBi4 trigonal bipyramids, edges with eight TeBi6 octahedra, and edges with three TeCsBi4 trigonal bipyramids. The corner-sharing octahedral tilt angles are 7°. In the second Te2- site, Te2- is bonded to one Cs1+ and four Bi+2.75+ atoms to form distorted TeCsBi4 trigonal bipyramids that share corners with three TeCs2Bi4 octahedra, corners with two equivalent TeCsBi4 trigonal bipyramids, and edges with three TeBi6 octahedra. The corner-sharing octahedra tilt angles range from 7–13°. In the third Te2- site, Te2- is bonded in a 7-coordinate geometry to three Cs1+, two equivalent Bi+2.75+, and two equivalent Te2- atoms. Both Te–Te bond lengths are 3.58 Å. In the fourth Te2- site, Te2- is bonded to two equivalent Cs1+ and four Bi+2.75+ atoms to form TeCs2Bi4 octahedra that share corners with two equivalent TeBi6 octahedra, corners with four TeCsBi4 trigonal bipyramids, and edges with seven TeBi6 octahedra. The corner-sharing octahedral tilt angles are 3°. In the fifth Te2- site, Te2- is bonded to six Bi+2.75+ atoms to form TeBi6 octahedra that share corners with four TeBi6 octahedra, edges with nine TeBi6 octahedra, and edges with two equivalent TeCsBi4 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 1–7°. In the sixth Te2- site, Te2- is bonded to six Bi+2.75+ atoms to form TeBi6 octahedra that share a cornercorner with one TeBi6 octahedra, corners with two equivalent TeCsBi4 trigonal bipyramids, edges with four TeBi6 octahedra, and edges with three TeCsBi4 trigonal bipyramids. The corner-sharing octahedral tilt angles are 1°. In the seventh Te2- site, Te2- is bonded to one Cs1+ and four Bi+2.75+ atoms to form distorted TeCsBi4 trigonal bipyramids that share corners with five TeBi6 octahedra, corners with two equivalent TeCsBi4 trigonal bipyramids, and edges with five TeBi6 octahedra. The corner-sharing octahedra tilt angles range from 5–35°. In the eighth Te2- site, Te2- is bonded in a 7-coordinate geometry to three Cs1+, two equivalent Bi+2.75+, and two equivalent Te2- atoms. In the ninth Te2- site, Te2- is bonded in a 7-coordinate geometry to three equivalent Cs1+, two equivalent Bi+2.75+, and two equivalent Te2- atoms. Both Te–Te bond lengths are 3.67 Å. In the tenth Te2- site, Te2- is bonded in a 5-coordinate geometry to two equivalent Cs1+ and three Bi+2.75+ atoms. In the eleventh Te2- site, Te2- is bonded in a 6-coordinate geometry to four equivalent Cs1+ and two equivalent Bi+2.75+ atoms. In the twelfth Te2- site, Te2- is bonded in a 5-coordinate geometry to five Bi+2.75+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs6Bi4O9 by Materials Project

Cs6Bi4O9 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are six inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 5-coordinate geometry to six O2- atoms. There are a spread of Cs–O bond distances ranging from 2.99–3.68 Å. In the second Cs1+ site, Cs1+ is bonded in a 5-coordinate geometry to six O2- atoms. There are a spread of Cs–O bond distances ranging from 3.11–3.73 Å. In the third Cs1+ site, Cs1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Cs–O bond distances ranging from 2.87–3.23 Å. In the fourth Cs1+ site, Cs1+ is bonded to six O2- atoms to form distorted CsO6 pentagonal pyramids that share a cornercorner with one CsO5 trigonal bipyramid, an edgeedge with one CsO6 pentagonal pyramid, and a faceface with one CsO5 trigonal bipyramid. There are a spread of Cs–O bond distances ranging from 3.09–3.30 Å. In the fifth Cs1+ site, Cs1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Cs–O bond distances ranging from 3.04–3.38 Å. In the sixth Cs1+ site, Cs1+ is bonded to five O2- atoms to form a mixture of distorted corner and face-sharing CsO5 trigonal bipyramids. There are a spread of Cs–O bond distances ranging from 3.02–3.53 Å. There are four inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded in a distorted see-saw-like geometry to four O2- atoms. There are a spread of Bi–O bond distances ranging from 2.06–2.54 Å. In the second Bi3+ site, Bi3+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There are a spread of Bi–O bond distances ranging from 2.05–2.16 Å. In the third Bi3+ site, Bi3+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Bi–O bond distances ranging from 2.06–2.86 Å. In the fourth Bi3+ site, Bi3+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are a spread of Bi–O bond distances ranging from 2.06–2.21 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to four Cs1+ and one Bi3+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to five Cs1+ and one Bi3+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to four Cs1+ and one Bi3+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to five Cs1+ and one Bi3+ atom. In the fifth O2- site, O2- is bonded in a 6-coordinate geometry to three Cs1+ and three Bi3+ atoms. In the sixth O2- site, O2- is bonded in a 6-coordinate geometry to five Cs1+ and one Bi3+ atom. In the seventh O2- site, O2- is bonded in a 5-coordinate geometry to three Cs1+ and two Bi3+ atoms. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to three Cs1+ and two Bi3+ atoms. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to two Cs1+ and two Bi3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs3Bi7Se12 by Materials Project

Cs3Bi7Se12 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are three inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Cs–Se bond distances ranging from 3.56–3.90 Å. In the second Cs1+ site, Cs1+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Cs–Se bond distances ranging from 3.63–3.92 Å. In the third Cs1+ site, Cs1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of Cs–Se bond distances ranging from 3.63–3.90 Å. There are seven inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing BiSe6 octahedra. The corner-sharing octahedra tilt angles range from 4–6°. There are a spread of Bi–Se bond distances ranging from 2.85–3.15 Å. In the second Bi3+ site, Bi3+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing BiSe6 octahedra. The corner-sharing octahedra tilt angles range from 4–11°. There are a spread of Bi–Se bond distances ranging from 2.82–3.25 Å. In the third Bi3+ site, Bi3+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are a spread of Bi–Se bond distances ranging from 2.85–3.13 Å. In the fourth Bi3+ site, Bi3+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing BiSe6 octahedra. The corner-sharing octahedra tilt angles range from 4–10°. There are a spread of Bi–Se bond distances ranging from 2.82–3.25 Å. In the fifth Bi3+ site, Bi3+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are a spread of Bi–Se bond distances ranging from 2.90–3.09 Å. In the sixth Bi3+ site, Bi3+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing BiSe6 octahedra. The corner-sharing octahedra tilt angles range from 4–6°. There are a spread of Bi–Se bond distances ranging from 2.84–3.15 Å. In the seventh Bi3+ site, Bi3+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing BiSe6 octahedra. The corner-sharing octahedra tilt angles range from 10–11°. There are a spread of Bi–Se bond distances ranging from 2.92–3.02 Å. There are twelve inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to two equivalent Cs1+ and three Bi3+ atoms to form SeCs2Bi3 square pyramids that share a cornercorner with one SeBi6 octahedra, corners with six SeCsBi4 trigonal bipyramids, edges with four SeCs3Bi3 octahedra, edges with two equivalent SeCs2Bi3 square pyramids, and edges with two SeCsBi4 trigonal bipyramids. The corner-sharing octahedral tilt angles are 6°. In the second Se2- site, Se2- is bonded to six Bi3+ atoms to form SeBi6 octahedra that share corners with three SeCs2Bi3 square pyramids, edges with six SeBi6 octahedra, an edgeedge with one SeCs2Bi3 square pyramid, and edges with four SeCsBi4 trigonal bipyramids. In the third Se2- site, Se2- is bonded in a 5-coordinate geometry to three Cs1+ and two equivalent Bi3+ atoms. In the fourth Se2- site, Se2- is bonded in a 5-coordinate geometry to three Cs1+ and two equivalent Bi3+ atoms. In the fifth Se2- site, Se2- is bonded to two equivalent Cs1+ and three Bi3+ atoms to form SeCs2Bi3 square pyramids that share corners with two equivalent SeBi6 octahedra, corners with seven SeCsBi4 trigonal bipyramids, edges with three SeBi6 octahedra, edges with two equivalent SeCs2Bi3 square pyramids, and an edgeedge with one SeCs2Bi3 trigonal bipyramid. The corner-sharing octahedral tilt angles are 6°. In the sixth Se2- site, Se2- is bonded to three Cs1+ and three Bi3+ atoms to form distorted SeCs3Bi3 octahedra that share corners with two equivalent SeBi6 octahedra, corners with five SeCsBi4 trigonal bipyramids, edges with five SeBi6 octahedra, and edges with two equivalent SeCs2Bi3 square pyramids. The corner-sharing octahedral tilt angles are 5°. In the seventh Se2- site, Se2- is bonded to one Cs1+ and four Bi3+ atoms to form SeCsBi4 trigonal bipyramids that share corners with two equivalent SeCs3Bi3 octahedra, corners with three SeCs2Bi3 square pyramids, corners with three SeCsBi4 trigonal bipyramids, edges with two equivalent SeBi6 octahedra, an edgeedge with one SeCs2Bi3 square pyramid, and edges with two equivalent SeCs2Bi3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 34°. In the eighth Se2- site, Se2- is bonded to two equivalent Cs1+ and three Bi3+ atoms to form distorted SeCs2Bi3 trigonal bipyramids that share a cornercorner with one SeBi6 octahedra, corners with four SeCs2Bi3 square pyramids, an edgeedge with one SeCs2Bi3 square pyramid, and edges with six SeCsBi4 trigonal bipyramids. The corner-sharing octahedral tilt angles are 2°. In the ninth Se2- site, Se2- is bonded to one Cs1+ and four Bi3+ atoms to form SeCsBi4 trigonal bipyramids that share a cornercorner with one SeCs3Bi3 octahedra, corners with two equivalent SeCs2Bi3 square pyramids, corners with five SeCsBi4 trigonal bipyramids, edges with two equivalent SeBi6 octahedra, and edges with three SeCs2Bi3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 9°. In the tenth Se2- site, Se2- is bonded in a 6-coordinate geometry to three Cs1+ and three Bi3+ atoms. In the eleventh Se2- site, Se2- is bonded to two equivalent Cs1+ and three Bi3+ atoms to form distorted SeCs2Bi3 trigonal bipyramids that share corners with three SeCs3Bi3 octahedra, corners with four SeCs2Bi3 square pyramids, corners with two equivalent SeCsBi4 trigonal bipyramids, edges with two equivalent SeBi6 octahedra, an edgeedge with one SeCs2Bi3 square pyramid, and edges with three SeCsBi4 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 7–42°. In the twelfth Se2- site, Se2- is bonded to six Bi3+ atoms to form SeBi6 octahedra that share corners with two equivalent SeCs3Bi3 octahedra, corners with two SeCs2Bi3 trigonal bipyramids, edges with five SeBi6 octahedra, edges with four SeCs2Bi3 square pyramids, and edges with two equivalent SeCsBi4 trigonal bipyramids. The corner-sharing octahedral tilt angles are 5°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsBiO2 by Materials Project

CsBiO2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Cs1+ is bonded in a 6-coordinate geometry to six equivalent O2- atoms. There are a spread of Cs–O bond distances ranging from 3.02–3.36 Å. Bi3+ is bonded in a see-saw-like geometry to four equivalent O2- atoms. There are two shorter (2.12 Å) and two longer (2.36 Å) Bi–O bond lengths. O2- is bonded in a 5-coordinate geometry to three equivalent Cs1+ and two equivalent Bi3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Structural and physical properties of 99 complex bulk chalcogenides crystals using first-principles calculations

Chalcogenide semiconductors and glasses have many applications in the civil and military fields, especially in relation to their electronic, optical and mechanical properties for energy conversion and in enviormental materials. However, they are much less systemically studied and their fundamental physical properties for a large class chalcogenide semiconductors are rather scattered and incomplete. Here, we present a detailed study using well defined first-principles calculations on the electronic structure, interatomic bonding, optical, and mechanical properties for 99 bulk chalcogenides including thirteen of these crytals which have never been calculated. Due to their unique composition and structures, these 99 bulk chalcogenides are divided into two main groups. The first group contains 54 quaternary crystals with the structure composition (A2BCQ4) (A = Ag, Cu; B = Zn, Cd, Hg, Mg, Sr, Ba; C = Si, Ge, Sn; Q = S, Se, Te), while the second group contains scattered ternary and quaternary chalcogenide crystals with a more diverse composition (AxByCzQn) (A = Ag, Cu, Ba, Cs, Li, Tl, K, Lu, Sr; B = Zn, Cd, Hg, Al, Ga, In, P, As, La, Lu, Pb, Cu, Ag; C = Si, Ge, Sn, As, Sb, Bi, Zr, Hf, Ga, In; Q = S, Se, Te; x=1, 2, 3; y=0, 1, 2, 5; z=0, 1, 2 and n=3, 4, 5, 6, 9). Moreover, the total bond order density (TBOD) is used as a single quantum mechanical metric to characterize the internal cohesion of these crystals enabling us to correlate them with the calculated properties, especially their mechanical properties. This work provides a very large database for bulk chalcogenides crucial for the future theoretical and experimental studies, opening opportunities for study the properties and potential application of a wide variety of chalcogenides.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2020

Materials Data on CsAg2BiS3 by Materials Project

CsBiAg2S3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Cs1+ is bonded in a 5-coordinate geometry to two equivalent Ag1+ and seven S2- atoms. There are one shorter (3.71 Å) and one longer (3.73 Å) Cs–Ag bond lengths. There are a spread of Cs–S bond distances ranging from 3.62–4.04 Å. There are two inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded in a linear geometry to two equivalent Cs1+ and two equivalent S2- atoms. There are one shorter (2.40 Å) and one longer (2.41 Å) Ag–S bond lengths. In the second Ag1+ site, Ag1+ is bonded in a distorted rectangular see-saw-like geometry to four S2- atoms. There are a spread of Ag–S bond distances ranging from 2.50–2.93 Å. Bi3+ is bonded to six S2- atoms to form edge-sharing BiS6 octahedra. There are a spread of Bi–S bond distances ranging from 2.72–3.05 Å. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a 3-coordinate geometry to four equivalent Cs1+ and three Ag1+ atoms. In the second S2- site, S2- is bonded to one Cs1+, two equivalent Ag1+, and three equivalent Bi3+ atoms to form a mixture of edge and corner-sharing SCsAg2Bi3 octahedra. The corner-sharing octahedra tilt angles range from 1–6°. In the third S2- site, S2- is bonded to two equivalent Cs1+, one Ag1+, and three equivalent Bi3+ atoms to form a mixture of edge and corner-sharing SCs2AgBi3 octahedra. The corner-sharing octahedra tilt angles range from 1–3°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsMg30BiO32 by Materials Project

CsMg30BiO32 is Caswellsilverite-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Cs1+ is bonded to six O2- atoms to form CsO6 octahedra that share corners with two equivalent BiO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.34 Å) and four longer (2.49 Å) Cs–O bond lengths. There are eight inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent CsO6 octahedra, corners with four MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 1.86–2.28 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent BiO6 octahedra, corners with four MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.01–2.21 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.11 Å) and two longer (2.24 Å) Mg–O bond lengths. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.14 Å) and two longer (2.21 Å) Mg–O bond lengths. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one CsO6 octahedra, an edgeedge with one BiO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 3–11°. There are a spread of Mg–O bond distances ranging from 2.08–2.29 Å. In the sixth Mg2+ site, Mg2+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–4°. There are a spread of Mg–O bond distances ranging from 2.17–2.24 Å. In the seventh Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one CsO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–14°. There are a spread of Mg–O bond distances ranging from 2.13–2.24 Å. In the eighth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one BiO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–5°. There are a spread of Mg–O bond distances ranging from 2.12–2.24 Å. Bi3+ is bonded to six O2- atoms to form BiO6 octahedra that share corners with two equivalent CsO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.11 Å) and four longer (2.35 Å) Bi–O bond lengths. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded to one Cs1+ and five Mg2+ atoms to form distorted OCsMg5 octahedra that share corners with six OMg5Bi octahedra and edges with twelve OCsMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. In the second O2- site, O2- is bonded to five Mg2+ and one Bi3+ atom to form OMg5Bi octahedra that share corners with six OCsMg5 octahedra and edges with twelve OMg5Bi octahedra. The corner-sharing octahedra tilt angles range from 0–7°. In the third O2- site, O2- is bonded to six Mg2+ atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. In the fourth O2- site, O2- is bonded to six Mg2+ atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the fifth O2- site, O2- is bonded to one Cs1+ and five Mg2+ atoms to form a mixture of distorted edge and corner-sharing OCsMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. There are a spread of O–Mg bond distances ranging from 1.86–2.24 Å. In the sixth O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra and edges with twelve OCsMg5 octahedra. The corner-sharing octahedra tilt angles range from 1–6°. In the seventh O2- site, O2- is bonded to one Cs1+, four equivalent Mg2+, and one Bi3+ atom to form OCsMg4Bi octahedra that share corners with six OCsMg4Bi octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the eighth O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six OCsMg4Bi octahedra and edges with twelve OCsMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the ninth O2- site, O2- is bonded to six Mg2+ atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs3Bi2Cl9 by Materials Project

Cs3Bi2Cl9 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are three inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded to twelve Cl1- atoms to form distorted CsCl12 cuboctahedra that share corners with nine CsCl12 cuboctahedra, a cornercorner with one BiCl6 octahedra, faces with seven CsCl12 cuboctahedra, and faces with six BiCl6 octahedra. The corner-sharing octahedral tilt angles are 18°. There are a spread of Cs–Cl bond distances ranging from 3.72–4.20 Å. In the second Cs1+ site, Cs1+ is bonded to twelve Cl1- atoms to form CsCl12 cuboctahedra that share corners with twelve CsCl12 cuboctahedra, faces with six CsCl12 cuboctahedra, and faces with five BiCl6 octahedra. There are a spread of Cs–Cl bond distances ranging from 3.79–3.99 Å. In the third Cs1+ site, Cs1+ is bonded to twelve Cl1- atoms to form CsCl12 cuboctahedra that share corners with nine CsCl12 cuboctahedra, corners with two equivalent BiCl6 octahedra, faces with seven CsCl12 cuboctahedra, and faces with four BiCl6 octahedra. The corner-sharing octahedral tilt angles are 28°. There are a spread of Cs–Cl bond distances ranging from 3.79–4.10 Å. There are two inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded to six Cl1- atoms to form BiCl6 octahedra that share corners with three equivalent BiCl6 octahedra and faces with eight CsCl12 cuboctahedra. The corner-sharing octahedral tilt angles are 2°. There are a spread of Bi–Cl bond distances ranging from 2.59–2.90 Å. In the second Bi3+ site, Bi3+ is bonded to six Cl1- atoms to form BiCl6 octahedra that share corners with three CsCl12 cuboctahedra, corners with three equivalent BiCl6 octahedra, and faces with seven CsCl12 cuboctahedra. The corner-sharing octahedral tilt angles are 2°. There are a spread of Bi–Cl bond distances ranging from 2.62–2.89 Å. There are six inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a distorted single-bond geometry to four Cs1+ and one Bi3+ atom. In the second Cl1- site, Cl1- is bonded in a distorted single-bond geometry to four Cs1+ and one Bi3+ atom. In the third Cl1- site, Cl1- is bonded in a 6-coordinate geometry to four Cs1+ and two Bi3+ atoms. In the fourth Cl1- site, Cl1- is bonded in a 5-coordinate geometry to four Cs1+ and two Bi3+ atoms. In the fifth Cl1- site, Cl1- is bonded in a distorted single-bond geometry to four Cs1+ and one Bi3+ atom. In the sixth Cl1- site, Cl1- is bonded in a distorted single-bond geometry to four Cs1+ and one Bi3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs3BiSe3 by Materials Project

Cs3BiSe3 crystallizes in the cubic P2_13 space group. The structure is three-dimensional. there are three inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 6-coordinate geometry to six equivalent Se2- atoms. There are three shorter (3.62 Å) and three longer (3.83 Å) Cs–Se bond lengths. In the second Cs1+ site, Cs1+ is bonded to six equivalent Se2- atoms to form a mixture of distorted corner, edge, and face-sharing CsSe6 octahedra. The corner-sharing octahedra tilt angles range from 33–43°. There are three shorter (3.63 Å) and three longer (3.81 Å) Cs–Se bond lengths. In the third Cs1+ site, Cs1+ is bonded to six equivalent Se2- atoms to form a mixture of corner, edge, and face-sharing CsSe6 octahedra. The corner-sharing octahedra tilt angles range from 33–60°. There are three shorter (3.90 Å) and three longer (4.03 Å) Cs–Se bond lengths. Bi3+ is bonded in a trigonal non-coplanar geometry to three equivalent Se2- atoms. All Bi–Se bond lengths are 2.70 Å. Se2- is bonded to six Cs1+ and one Bi3+ atom to form a mixture of distorted corner, edge, and face-sharing SeCs6Bi pentagonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Understanding the evolution of double perovskite band structure upon dimensional reduction

Recent investigations into the effects of dimensional reduction on halide double perovskites have revealed an intriguing change in band structure when the three-dimensional (3D) perovskite is reduced to a two-dimensional (2D) perovskite with inorganic sheets of monolayer thickness (n = 1). The indirect bandgap of 3D Cs 2 AgBiBr 6 becomes direct in the n = 1 perovskite whereas the direct bandgap of 3D Cs 2 AgTlBr 6 becomes indirect at the n = 1 limit. Here, we apply a linear combination of atomic orbitals approach to uncover the orbital basis for this bandgap symmetry transition with dimensional reduction. We adapt our previously established method for predicting band structures of 3D double perovskites for application to their 2D congeners, emphasizing new considerations required for the 2D lattice. In particular, we consider the inequivalence of the terminal and bridging halides and the consequences of applying translational symmetry only along two dimensions. The valence and conduction bands of the layered perovskites can be derived from symmetry adapted linear combinations of halide p orbitals propagated across the 2D lattice. The dispersion of each band is then determined by the bonding and antibonding interactions of the metal and halide orbitals, thus affording predictions of the essential features of the band structure. We demonstrate this analysis for 2D Ag–Bi and Ag–Tl perovskites with sheets of mono- and bilayer thickness, establishing a detailed understanding of their band structures, which enables us to identify the key factors that drive the bandgap symmetry transitions observed at the n = 1 limit. Importantly, these insights also allow us to make the general prediction that direct → indirect or indirect → direct bandgap transitions in the monolayer limit are most likely in double perovskite compositions that involve participation of metal d orbitals at the band edges or that have no metal-orbital contributions to the valence band, laying the groundwork for the targeted realization of this phenomenon.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on Cs2Bi8Se13 by Materials Project

Cs2Bi8Se13 is Orthorhombic Perovskite-like structured and crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 9-coordinate geometry to nine Se2- atoms. There are a spread of Cs–Se bond distances ranging from 3.63–4.11 Å. In the second Cs1+ site, Cs1+ is bonded in a 9-coordinate geometry to nine Se2- atoms. There are a spread of Cs–Se bond distances ranging from 3.68–3.95 Å. There are eight inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing BiSe6 octahedra. The corner-sharing octahedra tilt angles range from 5–7°. There are a spread of Bi–Se bond distances ranging from 2.92–3.07 Å. In the second Bi3+ site, Bi3+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing BiSe6 octahedra. The corner-sharing octahedra tilt angles range from 8–9°. There are a spread of Bi–Se bond distances ranging from 2.79–3.22 Å. In the third Bi3+ site, Bi3+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing BiSe6 octahedra. The corner-sharing octahedra tilt angles range from 5–14°. There are a spread of Bi–Se bond distances ranging from 2.80–3.27 Å. In the fourth Bi3+ site, Bi3+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles are 9°. There are a spread of Bi–Se bond distances ranging from 2.79–3.13 Å. In the fifth Bi3+ site, Bi3+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing BiSe6 octahedra. The corner-sharing octahedra tilt angles range from 7–9°. There are a spread of Bi–Se bond distances ranging from 2.84–3.19 Å. In the sixth Bi3+ site, Bi3+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing BiSe6 octahedra. The corner-sharing octahedra tilt angles range from 6–10°. There are a spread of Bi–Se bond distances ranging from 2.79–3.29 Å. In the seventh Bi3+ site, Bi3+ is bonded to five Se2- atoms to form BiSe5 square pyramids that share corners with two equivalent BiSe6 octahedra and edges with four equivalent BiSe5 square pyramids. The corner-sharing octahedral tilt angles are 67°. There are a spread of Bi–Se bond distances ranging from 2.73–2.99 Å. In the eighth Bi3+ site, Bi3+ is bonded to six Se2- atoms to form BiSe6 octahedra that share corners with three BiSe6 octahedra, corners with two equivalent BiSe5 square pyramids, and edges with five BiSe6 octahedra. The corner-sharing octahedra tilt angles range from 10–14°. There are a spread of Bi–Se bond distances ranging from 2.75–3.29 Å. There are thirteen inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to one Cs1+ and four Bi3+ atoms to form distorted SeCsBi4 trigonal bipyramids that share corners with five SeCs2Bi4 octahedra, corners with two equivalent SeCsBi4 trigonal bipyramids, edges with three SeBi6 octahedra, and edges with two equivalent SeBi5 square pyramids. The corner-sharing octahedra tilt angles range from 7–31°. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to three Bi3+ atoms. In the third Se2- site, Se2- is bonded to two equivalent Cs1+ and three equivalent Bi3+ atoms to form a mixture of distorted edge and corner-sharing SeCs2Bi3 trigonal bipyramids. In the fourth Se2- site, Se2- is bonded to two equivalent Cs1+ and four Bi3+ atoms to form distorted SeCs2Bi4 octahedra that share corners with two equivalent SeBi6 octahedra, corners with four SeCsBi4 trigonal bipyramids, and edges with seven SeBi6 octahedra. The corner-sharing octahedral tilt angles are 3°. In the fifth Se2- site, Se2- is bonded in a 5-coordinate geometry to three equivalent Cs1+ and two equivalent Bi3+ atoms. In the sixth Se2- site, Se2- is bonded to six Bi3+ atoms to form SeBi6 octahedra that share a cornercorner with one SeBi6 octahedra, corners with two equivalent SeCsBi4 trigonal bipyramids, edges with six SeBi6 octahedra, edges with two equivalent SeBi5 square pyramids, and edges with three SeCsBi4 trigonal bipyramids. The corner-sharing octahedral tilt angles are 9°. In the seventh Se2- site, Se2- is bonded in a 5-coordinate geometry to three Cs1+ and two equivalent Bi3+ atoms. In the eighth Se2- site, Se2- is bonded in a 5-coordinate geometry to two equivalent Cs1+ and three Bi3+ atoms. In the ninth Se2- site, Se2- is bonded in a 4-coordinate geometry to one Cs1+ and three equivalent Bi3+ atoms. In the tenth Se2- site, Se2- is bonded to six Bi3+ atoms to form SeBi6 octahedra that share corners with three SeBi6 octahedra, a cornercorner with one SeBi5 square pyramid, edges with nine SeBi6 octahedra, and edges with two equivalent SeCsBi4 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 3–9°. In the eleventh Se2- site, Se2- is bonded to five Bi3+ atoms to form SeBi5 square pyramids that share a cornercorner with one SeBi6 octahedra, corners with two equivalent SeCsBi4 trigonal bipyramids, edges with two equivalent SeBi6 octahedra, edges with two equivalent SeBi5 square pyramids, and edges with three SeCsBi4 trigonal bipyramids. The corner-sharing octahedral tilt angles are 5°. In the twelfth Se2- site, Se2- is bonded in a 5-coordinate geometry to three Cs1+ and two equivalent Bi3+ atoms. In the thirteenth Se2- site, Se2- is bonded to one Cs1+ and four Bi3+ atoms to form distorted SeCsBi4 trigonal bipyramids that share a cornercorner with one SeCs2Bi4 octahedra, corners with two equivalent SeBi5 square pyramids, corners with three SeCsBi4 trigonal bipyramids, edges with two equivalent SeBi6 octahedra, an edgeedge with one SeBi5 square pyramid, and edges with two equivalent SeCs2Bi3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 10°.

36 MATERIALS SCIENCE↗