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DOE OSTI2020

Materials Data on Cs2CuBrCl3 by Materials Project

Cs2CuBrCl3 is (La,Ba)CuO4-derived structured and crystallizes in the tetragonal I4mm space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a distorted q6 geometry to four equivalent Br1- and five Cl1- atoms. All Cs–Br bond lengths are 3.64 Å. There are four shorter (3.48 Å) and one longer (3.78 Å) Cs–Cl bond lengths. In the second Cs1+ site, Cs1+ is bonded in a distorted q6 geometry to one Br1- and eight Cl1- atoms. The Cs–Br bond length is 3.73 Å. There are four shorter (3.44 Å) and four longer (3.64 Å) Cs–Cl bond lengths. There are two inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded to one Br1- and five Cl1- atoms to form corner-sharing CuBrCl5 octahedra. The corner-sharing octahedral tilt angles are 2°. The Cu–Br bond length is 2.52 Å. There are one shorter (2.34 Å) and four longer (2.57 Å) Cu–Cl bond lengths. In the second Cu2+ site, Cu2+ is bonded to one Br1- and five Cl1- atoms to form corner-sharing CuBrCl5 octahedra. The corner-sharing octahedral tilt angles are 2°. The Cu–Br bond length is 2.52 Å. There are one shorter (2.34 Å) and four longer (2.57 Å) Cu–Cl bond lengths. Br1- is bonded to five Cs1+ and one Cu2+ atom to form distorted BrCs5Cu octahedra that share corners with four equivalent BrCs5Cu octahedra, corners with twelve equivalent ClCs4Cu2 octahedra, edges with four equivalent BrCs5Cu octahedra, and faces with four equivalent ClCs4Cu2 octahedra. The corner-sharing octahedra tilt angles range from 4–57°. There are two inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded to four Cs1+ and two equivalent Cu2+ atoms to form distorted ClCs4Cu2 octahedra that share corners with two equivalent ClCs4Cu2 octahedra, corners with six equivalent BrCs5Cu octahedra, edges with two equivalent ClCs4Cu2 octahedra, faces with two equivalent BrCs5Cu octahedra, and faces with four equivalent ClCs4Cu2 octahedra. The corner-sharing octahedra tilt angles range from 2–57°. In the second Cl1- site, Cl1- is bonded in a distorted single-bond geometry to five Cs1+ and one Cu2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsNd3 by Materials Project

CsNd3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Cs is bonded to twelve Nd atoms to form CsNd12 cuboctahedra that share corners with four equivalent CsNd12 cuboctahedra, corners with eight equivalent NdCs4Nd8 cuboctahedra, edges with eight equivalent CsNd12 cuboctahedra, edges with sixteen equivalent NdCs4Nd8 cuboctahedra, faces with four equivalent CsNd12 cuboctahedra, and faces with fourteen NdCs4Nd8 cuboctahedra. There are eight shorter (3.84 Å) and four longer (3.85 Å) Cs–Nd bond lengths. There are two inequivalent Nd sites. In the first Nd site, Nd is bonded to four equivalent Cs and eight Nd atoms to form NdCs4Nd8 cuboctahedra that share corners with twelve equivalent NdCs4Nd8 cuboctahedra, edges with eight equivalent CsNd12 cuboctahedra, edges with sixteen NdCs4Nd8 cuboctahedra, faces with four equivalent CsNd12 cuboctahedra, and faces with fourteen NdCs4Nd8 cuboctahedra. There are four shorter (3.84 Å) and four longer (3.85 Å) Nd–Nd bond lengths. In the second Nd site, Nd is bonded to four equivalent Cs and eight equivalent Nd atoms to form NdCs4Nd8 cuboctahedra that share corners with four equivalent NdCs4Nd8 cuboctahedra, corners with eight equivalent CsNd12 cuboctahedra, edges with twenty-four NdCs4Nd8 cuboctahedra, faces with six equivalent CsNd12 cuboctahedra, and faces with twelve NdCs4Nd8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsYb3 by Materials Project

CsYb3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Cs is bonded to twelve Yb atoms to form CsYb12 cuboctahedra that share corners with four equivalent CsYb12 cuboctahedra, corners with eight equivalent YbCs4Yb8 cuboctahedra, edges with eight equivalent CsYb12 cuboctahedra, edges with sixteen equivalent YbCs4Yb8 cuboctahedra, faces with four equivalent CsYb12 cuboctahedra, and faces with fourteen YbCs4Yb8 cuboctahedra. There are eight shorter (4.17 Å) and four longer (4.21 Å) Cs–Yb bond lengths. There are two inequivalent Yb sites. In the first Yb site, Yb is bonded to four equivalent Cs and eight Yb atoms to form distorted YbCs4Yb8 cuboctahedra that share corners with twelve equivalent YbCs4Yb8 cuboctahedra, edges with eight equivalent CsYb12 cuboctahedra, edges with sixteen YbCs4Yb8 cuboctahedra, faces with four equivalent CsYb12 cuboctahedra, and faces with fourteen YbCs4Yb8 cuboctahedra. There are four shorter (4.17 Å) and four longer (4.21 Å) Yb–Yb bond lengths. In the second Yb site, Yb is bonded to four equivalent Cs and eight equivalent Yb atoms to form YbCs4Yb8 cuboctahedra that share corners with four equivalent YbCs4Yb8 cuboctahedra, corners with eight equivalent CsYb12 cuboctahedra, edges with twenty-four YbCs4Yb8 cuboctahedra, faces with six equivalent CsYb12 cuboctahedra, and faces with twelve YbCs4Yb8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs2Al(TeO4)3 by Materials Project

Cs2Al(TeO4)3 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Cs is bonded to six O atoms to form distorted CsO6 octahedra that share corners with three equivalent AlO6 octahedra and corners with nine equivalent TeO6 octahedra. The corner-sharing octahedra tilt angles range from 66–72°. There are three shorter (3.09 Å) and three longer (3.12 Å) Cs–O bond lengths. Al is bonded to six equivalent O atoms to form AlO6 octahedra that share corners with six equivalent CsO6 octahedra and corners with six equivalent TeO6 octahedra. The corner-sharing octahedra tilt angles range from 42–66°. All Al–O bond lengths are 1.91 Å. Te is bonded to six O atoms to form TeO6 octahedra that share corners with two equivalent AlO6 octahedra, corners with four equivalent TeO6 octahedra, and corners with six equivalent CsO6 octahedra. The corner-sharing octahedra tilt angles range from 42–72°. There is two shorter (1.90 Å) and four longer (1.99 Å) Te–O bond length. There are two inequivalent O sites. In the first O site, O is bonded in a distorted bent 150 degrees geometry to one Cs, one Al, and one Te atom. In the second O site, O is bonded in a 2-coordinate geometry to one Cs and two equivalent Te atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs2KSiF7 by Materials Project

Cs2KSiF7 crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded to six F1- atoms to form distorted CsF6 octahedra that share corners with four SiF6 octahedra and corners with six equivalent CsF6 octahedra. The corner-sharing octahedra tilt angles range from 0–68°. There are a spread of Cs–F bond distances ranging from 3.03–3.16 Å. In the second Cs1+ site, Cs1+ is bonded in a 10-coordinate geometry to ten F1- atoms. There are a spread of Cs–F bond distances ranging from 2.96–3.16 Å. K1+ is bonded in a 10-coordinate geometry to ten F1- atoms. There are a spread of K–F bond distances ranging from 2.92–3.13 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to six F1- atoms to form SiF6 octahedra that share corners with four equivalent CsF6 octahedra. The corner-sharing octahedral tilt angles are 68°. There is two shorter (1.72 Å) and four longer (1.73 Å) Si–F bond length. In the second Si4+ site, Si4+ is bonded to six F1- atoms to form SiF6 octahedra that share corners with four equivalent CsF6 octahedra. The corner-sharing octahedral tilt angles are 67°. There is two shorter (1.72 Å) and four longer (1.73 Å) Si–F bond length. There are seven inequivalent F1- sites. In the first F1- site, F1- is bonded to four Cs1+ and two equivalent K1+ atoms to form corner-sharing FCs4K2 octahedra. The corner-sharing octahedra tilt angles range from 0–25°. There are two shorter (2.96 Å) and two longer (3.03 Å) F–Cs bond lengths. Both F–K bond lengths are 3.00 Å. In the second F1- site, F1- is bonded in a distorted single-bond geometry to one Cs1+, two equivalent K1+, and one Si4+ atom. In the third F1- site, F1- is bonded in a distorted single-bond geometry to two equivalent Cs1+, one K1+, and one Si4+ atom. In the fourth F1- site, F1- is bonded in a single-bond geometry to four Cs1+ and one Si4+ atom. In the fifth F1- site, F1- is bonded in a single-bond geometry to two equivalent Cs1+, two equivalent K1+, and one Si4+ atom. In the sixth F1- site, F1- is bonded to four Cs1+ and two equivalent K1+ atoms to form corner-sharing FCs4K2 octahedra. The corner-sharing octahedra tilt angles range from 0–25°. In the seventh F1- site, F1- is bonded to four Cs1+ and two equivalent K1+ atoms to form corner-sharing FCs4K2 octahedra. The corner-sharing octahedra tilt angles range from 0–25°. Both F–Cs bond lengths are 3.03 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs4Ge(PSe3)4 by Materials Project

Cs4Ge(PSe3)4 crystallizes in the orthorhombic Pca2_1 space group. The structure is three-dimensional. there are four inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 9-coordinate geometry to ten Se2- atoms. There are a spread of Cs–Se bond distances ranging from 3.78–4.40 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 3.76–4.21 Å. In the third 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 3.60–4.26 Å. In the fourth 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 3.61–4.27 Å. Ge2+ is bonded in a tetrahedral geometry to four Se2- atoms. There are three shorter (2.40 Å) and one longer (2.41 Å) Ge–Se bond lengths. There are four inequivalent P+4.50+ sites. In the first P+4.50+ site, P+4.50+ is bonded in a trigonal non-coplanar geometry to three Se2- atoms. There are a spread of P–Se bond distances ranging from 2.15–2.36 Å. In the second P+4.50+ site, P+4.50+ is bonded in a trigonal non-coplanar geometry to three Se2- atoms. There are a spread of P–Se bond distances ranging from 2.15–2.33 Å. In the third P+4.50+ site, P+4.50+ is bonded in a trigonal non-coplanar geometry to three Se2- atoms. There are two shorter (2.16 Å) and one longer (2.35 Å) P–Se bond lengths. In the fourth P+4.50+ site, P+4.50+ is bonded in a trigonal non-coplanar geometry to three Se2- atoms. There are a spread of P–Se bond distances ranging from 2.14–2.35 Å. There are twelve inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 1-coordinate geometry to three Cs1+ and one P+4.50+ atom. In the second Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Cs1+ and one P+4.50+ atom. In the third Se2- site, Se2- is bonded in a distorted water-like geometry to two equivalent Cs1+, one Ge2+, and one P+4.50+ atom. In the fourth Se2- site, Se2- is bonded in a distorted single-bond geometry to four Cs1+ and one P+4.50+ atom. In the fifth Se2- site, Se2- is bonded in a distorted single-bond geometry to three Cs1+ and one P+4.50+ atom. In the sixth Se2- site, Se2- is bonded in a distorted L-shaped geometry to one Cs1+, one Ge2+, and one P+4.50+ atom. In the seventh Se2- site, Se2- is bonded in a 2-coordinate geometry to two Cs1+, one Ge2+, and one P+4.50+ atom. In the eighth Se2- site, Se2- is bonded in a 1-coordinate geometry to four Cs1+ and one P+4.50+ atom. In the ninth Se2- site, Se2- is bonded in a 1-coordinate geometry to three Cs1+ and one P+4.50+ atom. In the tenth Se2- site, Se2- is bonded in a distorted L-shaped geometry to three Cs1+, one Ge2+, and one P+4.50+ atom. In the eleventh Se2- site, Se2- is bonded in a distorted single-bond geometry to four Cs1+ and one P+4.50+ atom. In the twelfth Se2- site, Se2- is bonded in a distorted single-bond geometry to three Cs1+ and one P+4.50+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs5V5FeCl6O13 by Materials Project

Cs5V5FeO13Cl6 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 8-coordinate geometry to four equivalent O2- and four equivalent Cl1- atoms. All Cs–O bond lengths are 3.27 Å. All Cs–Cl bond lengths are 3.53 Å. In the second Cs1+ site, Cs1+ is bonded in a 6-coordinate geometry to seven O2- and six Cl1- atoms. There are a spread of Cs–O bond distances ranging from 3.36–3.73 Å. There are a spread of Cs–Cl bond distances ranging from 3.63–3.97 Å. There are two inequivalent V5+ sites. In the first V5+ site, V5+ is bonded to five O2- atoms to form distorted corner-sharing VO5 trigonal bipyramids. There is one shorter (1.63 Å) and four longer (1.99 Å) V–O bond length. In the second V5+ site, V5+ is bonded to four O2- atoms to form VO4 tetrahedra that share corners with two equivalent VO4 tetrahedra and a cornercorner with one VO5 trigonal bipyramid. There are a spread of V–O bond distances ranging from 1.64–1.81 Å. Fe2+ is bonded in an octahedral geometry to six Cl1- atoms. There are two shorter (2.38 Å) and four longer (2.46 Å) Fe–Cl bond lengths. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to four equivalent Cs1+ and one V5+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to three Cs1+ and one V5+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Cs1+ and two V5+ atoms. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Cs1+ and two equivalent V5+ atoms. There are two inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a 1-coordinate geometry to five Cs1+ and one Fe2+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to four equivalent Cs1+ and one Fe2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsSr3 by Materials Project

CsSr3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Cs is bonded to twelve Sr atoms to form CsSr12 cuboctahedra that share corners with four equivalent CsSr12 cuboctahedra, corners with eight equivalent SrCs4Sr8 cuboctahedra, edges with eight equivalent CsSr12 cuboctahedra, edges with sixteen equivalent SrCs4Sr8 cuboctahedra, faces with four equivalent CsSr12 cuboctahedra, and faces with fourteen SrCs4Sr8 cuboctahedra. There are eight shorter (4.45 Å) and four longer (4.50 Å) Cs–Sr bond lengths. There are two inequivalent Sr sites. In the first Sr site, Sr is bonded to four equivalent Cs and eight Sr atoms to form SrCs4Sr8 cuboctahedra that share corners with twelve equivalent SrCs4Sr8 cuboctahedra, edges with eight equivalent CsSr12 cuboctahedra, edges with sixteen SrCs4Sr8 cuboctahedra, faces with four equivalent CsSr12 cuboctahedra, and faces with fourteen SrCs4Sr8 cuboctahedra. There are four shorter (4.45 Å) and four longer (4.50 Å) Sr–Sr bond lengths. In the second Sr site, Sr is bonded to four equivalent Cs and eight equivalent Sr atoms to form SrCs4Sr8 cuboctahedra that share corners with four equivalent SrCs4Sr8 cuboctahedra, corners with eight equivalent CsSr12 cuboctahedra, edges with twenty-four SrCs4Sr8 cuboctahedra, faces with six equivalent CsSr12 cuboctahedra, and faces with twelve SrCs4Sr8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsLa(TaBr3)6 by Materials Project

CsLa(TaBr3)6 crystallizes in the trigonal P-31c space group. The structure is three-dimensional. Cs is bonded in a 12-coordinate geometry to twelve Br atoms. There are six shorter (4.09 Å) and six longer (4.24 Å) Cs–Br bond lengths. La is bonded in an octahedral geometry to six equivalent Br atoms. All La–Br bond lengths are 3.00 Å. Ta is bonded in a 5-coordinate geometry to five Br atoms. There are a spread of Ta–Br bond distances ranging from 2.61–2.96 Å. There are three inequivalent Br sites. In the first Br site, Br is bonded in a 2-coordinate geometry to two equivalent Ta atoms. In the second Br site, Br is bonded in a 3-coordinate geometry to one Cs, one La, and one Ta atom. In the third Br site, Br is bonded in a 3-coordinate geometry to one Cs and two equivalent Ta atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs4Sr3(PO3)12 by Materials Project

Cs4Sr3(PO3)12 crystallizes in the cubic I-43d space group. The structure is three-dimensional. Cs is bonded in a 6-coordinate geometry to six O atoms. There are three shorter (3.20 Å) and three longer (3.33 Å) Cs–O bond lengths. Sr is bonded in a 8-coordinate geometry to eight O atoms. There are four shorter (2.59 Å) and four longer (2.71 Å) Sr–O bond lengths. P is bonded to four O atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.50–1.63 Å. There are three inequivalent O sites. In the first O site, O is bonded in a distorted single-bond geometry to one Cs, one Sr, and one P atom. In the second O site, O is bonded in a bent 120 degrees geometry to two equivalent P atoms. In the third O site, O is bonded in a distorted single-bond geometry to one Cs, one Sr, and one P atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs2MgO2 by Materials Project

Cs2MgO2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are four inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Cs–O bond distances ranging from 2.93–3.20 Å. In the second Cs1+ site, Cs1+ is bonded to four O2- atoms to form distorted CsO4 trigonal pyramids that share a cornercorner with one MgO4 tetrahedra, corners with two equivalent CsO4 trigonal pyramids, and an edgeedge with one MgO4 tetrahedra. There are a spread of Cs–O bond distances ranging from 2.99–3.20 Å. In the third Cs1+ site, Cs1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Cs–O bond distances ranging from 2.98–3.12 Å. In the fourth Cs1+ site, Cs1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Cs–O bond distances ranging from 3.09–3.43 Å. There are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a distorted trigonal planar geometry to three O2- atoms. There is one shorter (1.90 Å) and two longer (1.96 Å) Mg–O bond length. In the second Mg2+ site, Mg2+ is bonded to four O2- atoms to form distorted MgO4 tetrahedra that share a cornercorner with one CsO4 trigonal pyramid, an edgeedge with one MgO4 tetrahedra, and an edgeedge with one CsO4 trigonal pyramid. There are a spread of Mg–O bond distances ranging from 2.01–2.05 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to five Cs1+ and one Mg2+ atom. In the second O2- site, O2- is bonded in a distorted L-shaped geometry to four Cs1+ and two equivalent Mg2+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to three Cs1+ and two Mg2+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to four Cs1+ and two Mg2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs3CoI4NO3 by Materials Project

Cs3CoNO3I4 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 1-coordinate geometry to three O2- and six I1- atoms. There are one shorter (3.13 Å) and two longer (3.27 Å) Cs–O bond lengths. There are a spread of Cs–I bond distances ranging from 3.91–4.01 Å. In the second Cs1+ site, Cs1+ is bonded in a 9-coordinate geometry to three O2- and six I1- atoms. There are a spread of Cs–O bond distances ranging from 3.19–3.44 Å. There are a spread of Cs–I bond distances ranging from 4.04–4.24 Å. Co2+ is bonded in a tetrahedral geometry to four I1- atoms. There are a spread of Co–I bond distances ranging from 2.63–2.65 Å. N5+ is bonded in a trigonal planar geometry to three O2- atoms. All N–O bond lengths are 1.27 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to three Cs1+ and one N5+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to three Cs1+ and one N5+ atom. There are three inequivalent I1- sites. In the first I1- site, I1- is bonded in a 1-coordinate geometry to four Cs1+ and one Co2+ atom. In the second I1- site, I1- is bonded in a distorted single-bond geometry to five Cs1+ and one Co2+ atom. In the third I1- site, I1- is bonded in a 1-coordinate geometry to five Cs1+ and one Co2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs3GeSe3 by Materials Project

Cs3GeSe3 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are four inequivalent Cs1+ sites. In the first 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 3.53–4.04 Å. In the second 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 3.69–3.96 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 3.56–3.84 Å. In the fourth 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 3.68–3.73 Å. Ge3+ is bonded in a trigonal non-coplanar geometry to three Se2- atoms. There are one shorter (2.40 Å) and two longer (2.42 Å) Ge–Se bond lengths. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 7-coordinate geometry to six Cs1+ and one Ge3+ atom. In the second Se2- site, Se2- is bonded in a 1-coordinate geometry to six Cs1+ and one Ge3+ atom. In the third Se2- site, Se2- is bonded in a 7-coordinate geometry to six Cs1+ and one Ge3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsSe4 by Materials Project

CsSe4 crystallizes in the orthorhombic Pbcm space group. The structure is three-dimensional. there are four inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 10-coordinate geometry to ten Se+0.25- atoms. There are a spread of Cs–Se bond distances ranging from 3.67–4.21 Å. In the second Cs1+ site, Cs1+ is bonded in a 10-coordinate geometry to ten Se+0.25- atoms. There are a spread of Cs–Se bond distances ranging from 3.73–4.23 Å. In the third Cs1+ site, Cs1+ is bonded in a 10-coordinate geometry to ten Se+0.25- atoms. There are a spread of Cs–Se bond distances ranging from 3.70–4.25 Å. In the fourth Cs1+ site, Cs1+ is bonded in a 12-coordinate geometry to twelve Se+0.25- atoms. There are a spread of Cs–Se bond distances ranging from 3.65–4.35 Å. There are nine inequivalent Se+0.25- sites. In the first Se+0.25- site, Se+0.25- is bonded in a 5-coordinate geometry to three Cs1+ and two Se+0.25- atoms. There are one shorter (2.38 Å) and one longer (2.39 Å) Se–Se bond lengths. In the second Se+0.25- site, Se+0.25- is bonded to two equivalent Cs1+ and four Se+0.25- atoms to form corner-sharing SeCs2Se4 octahedra. The corner-sharing octahedral tilt angles are 48°. There are two shorter (2.52 Å) and two longer (2.92 Å) Se–Se bond lengths. In the third Se+0.25- site, Se+0.25- is bonded in a 6-coordinate geometry to three Cs1+ and three Se+0.25- atoms. There are one shorter (2.37 Å) and one longer (3.38 Å) Se–Se bond lengths. In the fourth Se+0.25- site, Se+0.25- is bonded in a 6-coordinate geometry to four Cs1+ and two Se+0.25- atoms. The Se–Se bond length is 3.07 Å. In the fifth Se+0.25- site, Se+0.25- is bonded in a 3-coordinate geometry to two equivalent Cs1+ and two equivalent Se+0.25- atoms. Both Se–Se bond lengths are 2.39 Å. In the sixth Se+0.25- site, Se+0.25- is bonded in a 3-coordinate geometry to three Cs1+ and two Se+0.25- atoms. The Se–Se bond length is 2.41 Å. In the seventh Se+0.25- site, Se+0.25- is bonded in a 5-coordinate geometry to two Cs1+ and three Se+0.25- atoms. The Se–Se bond length is 2.42 Å. In the eighth Se+0.25- site, Se+0.25- is bonded in a 4-coordinate geometry to two Cs1+ and two Se+0.25- atoms. In the ninth Se+0.25- site, Se+0.25- is bonded in a 2-coordinate geometry to two Cs1+ and three Se+0.25- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Characterization of Tank 11H Samples from Tank Closure Cesium Removal (TCCR) Batch 3 - Intermediate and Final Samples

Savannah River Remediation (SRR) is currently operating the Tank Closure Cesium Removal (TCCR) process to remove 137 Cs from tank waste supernate using an ion exchange process. The TCCR unit processes dissolved salt from Tank 10H through a series of ion exchange columns containing crystalline silicotitanate (CST) and the effluent is then discharged to Tank 11H. Four interim samples pulled from Tank 11H during and just after the completion of processing of Batch 3 through the TCCR process have been analyzed for 137 Cs activity and density. The 137 Cs activity was found to decrease with each subsequent sample, which is consistent with the addition of decontaminated solution to Tank 11H. When compared to the expected composition from mixing the Tank 10H Batch 3 feed with the material already present in Tank 11H, the bulk chemical composition was as expected. A corrosion control sample collected from Tank 11H in June 2020 showed changes in the chemical composition and 137 Cs activity when compared to the composition measured at the end of Batch 2 processing. As there were no additions made to the tank during this period, these changes were attributed to leaching of the solids present in Tank 11H. Additional analyses of the 4 th interim sample are pending and will be documented in a revision to this report.

11H↗
DOE OSTI2022

Characterization of Tank 11H Samples from Tank Closure Cesium Removal 1A (TCCR 1A) Batch 1

Savannah River Mission Completion (SRMC) is currently operating the Tank Closure Cesium Removal 1A (TCCR 1A) process to remove 137 Cs from tank waste supernate using an ion exchange process. The TCCR 1A unit processes dissolved salt fed from Tank 10H through a series of ion exchange columns containing crystalline silicotitanate (CST, IONSIV TM R9120-B, 30x60) and the effluent is then discharged to Tank 11H. In support of the TCCR 1A program, SRNL analyzed samples taken from Tank 11H (without tank mixing) before, during, and at the completion of TCCR 1A Batch 1 processing. Tank 11H serves as the receipt tank for the filtered and cesium removed product from the TCCR 1A system. Processing of Batch 1 commenced on January 13, 2022 and completed on February 17, 2022, after processing approximately 70,100 gallons. A pre-production sample was collected from the heel remaining in Tank 11H just before Batch 1 processing began. In addition, five interim surface samples were collected from Tank 11H during processing, and both a surface and a variable depth sample (VDS, ~7” from tank bottom) were collected just after processing completed. Analysis of all samples included density and gamma spectroscopy, in addition to a more comprehensive suite of analytes for the pre- and post-production samples. The density of the pre-production sample was the highest of all samples measured and was then observed to decrease for the first two interim samples, followed by becoming fairly consistent for the remainder of the samples (~1.3 g/mL). The density of 1.3 g/mL is similar to the density measured for one of the three Tank 10H qualification samples (HTF-10-21-126). The 137 Cs activity was found to decrease as additional decontaminated effluent from the TCCR columns was added to Tank 11H during processing; however, an increase in activity was observed during periods of no processing which can be attributed to leaching of 137 Cs from the known solids in Tank 11H. The Cs isotope concentrations in the Tank 11H postproduction surface sample were determined to be 99.7-99.8% lower than the concentrations measured in the Tank 10H feed as measured by mass spectrometry.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Understanding the Instability of the Halide Perovskite CsPbI 3 through Temperature-Dependent Structural Analysis

Despite the tremendous interest in halide perovskite solar cells, the structural reasons that cause the all-inorganic perovskite CsPbI 3 to be unstable at room temperature remain mysterious, especially since many tolerance-factor-based approaches predict CsPbI 3 should be stable as a perovskite. Here single-crystal X-ray diffraction and X-ray pair distribution function (PDF) measurements characterize bulk perovskite CsPbI3 from 100 to 295 K to elucidate its thermodynamic instability. While Cs occupies a single site from 100 to 150 K, it splits between two sites from 175 to 295 K with the second site having a lower effective coordination number, which, along with other structural parameters, suggests that Cs rattles in its coordination polyhedron. PDF measurements reveal that on the length scale of the unit cell, the Pb-I octahedra concurrently become greatly distorted, with one of the I-Pb-I angles approaching 82° compared to the ideal 90°. The rattling of Cs, low number of Cs-I contacts, and high degree of octahedral distortion cause the instability of perovskite-phase CsPbI 3 . These results reveal the limitations of tolerance factors in predicting perovskite stability and provide detailed structural information that suggests methods to engineer stable CsPbI 3 -based solar cells.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Endothermic Charge Separation Occurs Spontaneously in Non–Fullerene Acceptor/Polymer Bulk Heterojunction

Organic photovoltaics (OPVs) based on non-fullerene acceptors (NFAs) have achieved a power conversion efficiency close to 20%. These NFA OPVs can generate free carriers efficiently despite a very small energy level offset at the donor/acceptor interface. Why these NFAs can enable efficient charge separation (CS) with low energy losses remains an open question. Here, the CS process in the PM6:Y6 bulk heterojunction is probed by time-resolved two-photon photoemission spectroscopy. It is found that the CS, the conversion from bound charge transfer (CT) excitons to free carriers, is an endothermic process with an enthalpy barrier of 0.15 eV. The CS can occur spontaneously despite being an endothermic process, which implies that it is driven by entropy. It is further argued that the morphology of the PM6:Y6 film and the anisotropic electron delocalization restrict the electron and hole wavefunctions within the CT exciton such that they can primarily contact each other through point-like junctions. Furthermore, this configuration can maximize the entropic driving force.

36 MATERIALS SCIENCE↗