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DOE OSTI2020

Materials Data on Ta4AlN3 by Materials Project

Ta4AlN3 is MAX Phase-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Ta sites. In the first Ta site, Ta is bonded to six N atoms to form a mixture of distorted edge and corner-sharing TaN6 pentagonal pyramids. There are three shorter (2.21 Å) and three longer (2.23 Å) Ta–N bond lengths. In the second Ta site, Ta is bonded in a 3-coordinate geometry to three equivalent Al and three equivalent N atoms. All Ta–Al bond lengths are 2.81 Å. All Ta–N bond lengths are 2.23 Å. Al is bonded to six equivalent Ta and six equivalent Al atoms to form distorted AlTa6Al6 cuboctahedra that share corners with six equivalent AlTa6Al6 cuboctahedra, corners with six equivalent NTa6 octahedra, edges with six equivalent AlTa6Al6 cuboctahedra, edges with six equivalent NTa6 octahedra, and faces with six equivalent AlTa6Al6 cuboctahedra. The corner-sharing octahedral tilt angles are 13°. All Al–Al bond lengths are 2.98 Å. There are two inequivalent N sites. In the first N site, N is bonded to six equivalent Ta atoms to form a mixture of edge, face, and corner-sharing NTa6 octahedra. The corner-sharing octahedral tilt angles are 46°. In the second N site, N is bonded to six Ta atoms to form NTa6 octahedra that share corners with three equivalent AlTa6Al6 cuboctahedra, corners with six equivalent NTa6 octahedra, edges with three equivalent AlTa6Al6 cuboctahedra, edges with six equivalent NTa6 octahedra, and a faceface with one NTa6 octahedra. The corner-sharing octahedral tilt angles are 46°.

36 MATERIALS SCIENCE↗
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Materials Data on Ta3B2Ru5 by Materials Project

Ta3Ru5B2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. there are two inequivalent Ta sites. In the first Ta site, Ta is bonded in a 11-coordinate geometry to ten Ru and three equivalent B atoms. There are a spread of Ta–Ru bond distances ranging from 2.80–2.96 Å. There are one shorter (2.71 Å) and two longer (2.86 Å) Ta–B bond lengths. In the second Ta site, Ta is bonded in a body-centered cubic geometry to eight equivalent Ru atoms. All Ta–Ru bond lengths are 2.65 Å. There are two inequivalent Ru sites. In the first Ru site, Ru is bonded in a 8-coordinate geometry to six Ta and two equivalent B atoms. Both Ru–B bond lengths are 2.19 Å. In the second Ru site, Ru is bonded in a distorted body-centered cubic geometry to four equivalent Ta and four equivalent B atoms. All Ru–B bond lengths are 2.22 Å. B is bonded in a 6-coordinate geometry to three equivalent Ta and six Ru atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta3Co5B2 by Materials Project

Ta3Co5B2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. there are two inequivalent Ta sites. In the first Ta site, Ta is bonded in a body-centered cubic geometry to eight equivalent Co atoms. All Ta–Co bond lengths are 2.53 Å. In the second Ta site, Ta is bonded in a 1-coordinate geometry to ten Co and three equivalent B atoms. There are a spread of Ta–Co bond distances ranging from 2.64–2.76 Å. There are one shorter (2.46 Å) and two longer (2.51 Å) Ta–B bond lengths. There are two inequivalent Co sites. In the first Co site, Co is bonded to four equivalent Ta, four equivalent Co, and four equivalent B atoms to form distorted face-sharing CoTa4Co4B4 cuboctahedra. All Co–Co bond lengths are 2.42 Å. All Co–B bond lengths are 2.15 Å. In the second Co site, Co is bonded in a 4-coordinate geometry to six Ta, four Co, and two equivalent B atoms. There are one shorter (2.49 Å) and two longer (2.74 Å) Co–Co bond lengths. Both Co–B bond lengths are 2.15 Å. B is bonded in a 9-coordinate geometry to three equivalent Ta and six Co atoms.

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Materials Data on MgTa3 by Materials Project

MgTa3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Mg is bonded to twelve Ta atoms to form MgTa12 cuboctahedra that share corners with six equivalent MgTa12 cuboctahedra, corners with twelve TaMg4Ta8 cuboctahedra, edges with eighteen TaMg4Ta8 cuboctahedra, faces with eight equivalent MgTa12 cuboctahedra, and faces with twelve TaMg4Ta8 cuboctahedra. There are six shorter (2.98 Å) and six longer (2.99 Å) Mg–Ta bond lengths. There are two inequivalent Ta sites. In the first Ta site, Ta is bonded to four equivalent Mg and eight Ta atoms to form TaMg4Ta8 cuboctahedra that share corners with four equivalent MgTa12 cuboctahedra, corners with fourteen TaMg4Ta8 cuboctahedra, edges with six equivalent MgTa12 cuboctahedra, edges with twelve TaMg4Ta8 cuboctahedra, faces with four equivalent MgTa12 cuboctahedra, and faces with sixteen TaMg4Ta8 cuboctahedra. There are a spread of Ta–Ta bond distances ranging from 2.90–3.05 Å. In the second Ta site, Ta is bonded to four equivalent Mg and eight equivalent Ta atoms to form TaMg4Ta8 cuboctahedra that share corners with four equivalent MgTa12 cuboctahedra, corners with fourteen TaMg4Ta8 cuboctahedra, edges with six equivalent MgTa12 cuboctahedra, edges with twelve equivalent TaMg4Ta8 cuboctahedra, faces with four equivalent MgTa12 cuboctahedra, and faces with sixteen TaMg4Ta8 cuboctahedra.

36 MATERIALS SCIENCE↗
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Materials Data on DyTa3 by Materials Project

DyTa3 is alpha bismuth trifluoride structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Dy is bonded in a distorted body-centered cubic geometry to fourteen Ta atoms. There are eight shorter (2.98 Å) and six longer (3.44 Å) Dy–Ta bond lengths. There are two inequivalent Ta sites. In the first Ta site, Ta is bonded in a distorted body-centered cubic geometry to four equivalent Dy and four equivalent Ta atoms. All Ta–Ta bond lengths are 2.98 Å. In the second Ta site, Ta is bonded in a 8-coordinate geometry to six equivalent Dy and eight equivalent Ta atoms.

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Materials Data on NdTa3 by Materials Project

NdTa3 is alpha bismuth trifluoride structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Nd is bonded in a distorted body-centered cubic geometry to fourteen Ta atoms. There are eight shorter (3.00 Å) and six longer (3.47 Å) Nd–Ta bond lengths. There are two inequivalent Ta sites. In the first Ta site, Ta is bonded in a 8-coordinate geometry to four equivalent Nd and four equivalent Ta atoms. All Ta–Ta bond lengths are 3.00 Å. In the second Ta site, Ta is bonded in a 8-coordinate geometry to six equivalent Nd and eight equivalent Ta atoms.

36 MATERIALS SCIENCE↗
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Materials Data on Ta3N by Materials Project

Ta3N is H-Phase-derived structured and crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. there are two inequivalent Ta sites. In the first Ta site, Ta is bonded to twelve Ta atoms to form TaTa12 cuboctahedra that share corners with six equivalent TaTa12 cuboctahedra, corners with twelve equivalent NTa6 octahedra, edges with six equivalent TaTa12 cuboctahedra, faces with six equivalent TaTa12 cuboctahedra, and faces with two equivalent NTa6 octahedra. The corner-sharing octahedral tilt angles are 44°. There are six shorter (3.01 Å) and six longer (3.03 Å) Ta–Ta bond lengths. In the second Ta site, Ta is bonded in a distorted T-shaped geometry to three equivalent Ta and three equivalent N atoms. All Ta–N bond lengths are 2.19 Å. N is bonded to six equivalent Ta atoms to form NTa6 octahedra that share corners with twelve equivalent TaTa12 cuboctahedra, edges with six equivalent NTa6 octahedra, and faces with two equivalent TaTa12 cuboctahedra.

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Materials Data on Ta3Se12I by Materials Project

Ta3Se12I crystallizes in the tetragonal P4/mnc space group. The structure is three-dimensional. there are two inequivalent Ta+4.33+ sites. In the first Ta+4.33+ site, Ta+4.33+ is bonded to eight Se1- atoms to form distorted face-sharing TaSe8 hexagonal bipyramids. There are a spread of Ta–Se bond distances ranging from 2.65–2.75 Å. In the second Ta+4.33+ site, Ta+4.33+ is bonded in a 8-coordinate geometry to eight Se1- atoms. There are four shorter (2.59 Å) and four longer (2.77 Å) Ta–Se bond lengths. There are four inequivalent Se1- sites. In the first Se1- site, Se1- is bonded in a 2-coordinate geometry to two Ta+4.33+ and one I1- atom. The Se–I bond length is 3.35 Å. In the second Se1- site, Se1- is bonded in a 2-coordinate geometry to two equivalent Ta+4.33+ and one Se1- atom. The Se–Se bond length is 2.38 Å. In the third Se1- site, Se1- is bonded in a 2-coordinate geometry to two Ta+4.33+ atoms. In the fourth Se1- site, Se1- is bonded in a 2-coordinate geometry to two equivalent Ta+4.33+, one Se1-, and two equivalent I1- atoms. Both Se–I bond lengths are 4.01 Å. I1- is bonded in a 4-coordinate geometry to eight Se1- atoms.

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Materials Data on Ta2CN by Materials Project

Ta2CN is Caswellsilverite-like structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. there are two inequivalent Ta+3.50+ sites. In the first Ta+3.50+ site, Ta+3.50+ is bonded to two equivalent C4- and four equivalent N3- atoms to form a mixture of corner and edge-sharing TaC2N4 octahedra. The corner-sharing octahedral tilt angles are 0°. Both Ta–C bond lengths are 2.23 Å. All Ta–N bond lengths are 2.23 Å. In the second Ta+3.50+ site, Ta+3.50+ is bonded to four equivalent C4- and two equivalent N3- atoms to form TaC4N2 octahedra that share corners with six equivalent TaC4N2 octahedra and edges with twelve TaC2N4 octahedra. The corner-sharing octahedral tilt angles are 0°. All Ta–C bond lengths are 2.23 Å. Both Ta–N bond lengths are 2.23 Å. C4- is bonded to six Ta+3.50+ atoms to form CTa6 octahedra that share corners with six equivalent CTa6 octahedra, edges with four equivalent CTa6 octahedra, and edges with eight equivalent NTa6 octahedra. The corner-sharing octahedral tilt angles are 0°. N3- is bonded to six Ta+3.50+ atoms to form NTa6 octahedra that share corners with six equivalent NTa6 octahedra, edges with four equivalent NTa6 octahedra, and edges with eight equivalent CTa6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
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Materials Data on MgTa3 by Materials Project

MgTa3 is alpha bismuth trifluoride structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Mg is bonded in a distorted body-centered cubic geometry to fourteen Ta atoms. There are eight shorter (2.89 Å) and six longer (3.33 Å) Mg–Ta bond lengths. There are two inequivalent Ta sites. In the first Ta site, Ta is bonded in a distorted body-centered cubic geometry to four equivalent Mg and four equivalent Ta atoms. All Ta–Ta bond lengths are 2.89 Å. In the second Ta site, Ta is bonded in a 8-coordinate geometry to six equivalent Mg and eight equivalent Ta atoms.

36 MATERIALS SCIENCE↗
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Materials Data on Sc4TaFe19P12 by Materials Project

Sc4TaFe19P12 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are four inequivalent Sc sites. In the first Sc site, Sc is bonded in a 8-coordinate geometry to six P atoms. There are four shorter (2.74 Å) and two longer (2.81 Å) Sc–P bond lengths. In the second Sc site, Sc is bonded in a 6-coordinate geometry to six P atoms. There are a spread of Sc–P bond distances ranging from 2.71–2.84 Å. In the third Sc site, Sc is bonded in a 6-coordinate geometry to six P atoms. There are a spread of Sc–P bond distances ranging from 2.73–2.80 Å. In the fourth Sc site, Sc is bonded in a 6-coordinate geometry to six P atoms. There are a spread of Sc–P bond distances ranging from 2.70–2.76 Å. Ta is bonded in a 5-coordinate geometry to eight Fe and five P atoms. There are a spread of Ta–Fe bond distances ranging from 2.61–2.81 Å. There are a spread of Ta–P bond distances ranging from 2.49–2.61 Å. There are nineteen inequivalent Fe sites. In the first Fe site, Fe is bonded to four P atoms to form a mixture of distorted corner and edge-sharing FeP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.18–2.33 Å. In the second Fe site, Fe is bonded to four P atoms to form a mixture of distorted corner and edge-sharing FeP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.15–2.32 Å. In the third Fe site, Fe is bonded in a 4-coordinate geometry to two equivalent Ta and four P atoms. There are a spread of Fe–P bond distances ranging from 2.28–2.41 Å. In the fourth Fe site, Fe is bonded to four P atoms to form distorted FeP4 tetrahedra that share corners with twelve FeP4 tetrahedra and edges with three FeTaP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.15–2.31 Å. In the fifth Fe site, Fe is bonded to four P atoms to form a mixture of distorted corner and edge-sharing FeP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.26–2.33 Å. In the sixth Fe site, Fe is bonded to one Ta and four P atoms to form distorted FeTaP4 tetrahedra that share corners with six FeP4 tetrahedra, edges with four FeP4 tetrahedra, and faces with two equivalent FeTa2P4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.24–2.28 Å. In the seventh Fe site, Fe is bonded to four P atoms to form a mixture of distorted corner and edge-sharing FeP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.28–2.32 Å. In the eighth Fe site, Fe is bonded to four P atoms to form a mixture of distorted corner and edge-sharing FeP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.21–2.28 Å. In the ninth Fe site, Fe is bonded to four P atoms to form a mixture of distorted corner and edge-sharing FeP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.20–2.28 Å. In the tenth Fe site, Fe is bonded to four P atoms to form a mixture of distorted corner and edge-sharing FeP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.19–2.27 Å. In the eleventh Fe site, Fe is bonded to four P atoms to form a mixture of distorted corner and edge-sharing FeP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.18–2.28 Å. In the twelfth Fe site, Fe is bonded to two equivalent Ta and four P atoms to form distorted FeTa2P4 tetrahedra that share corners with eight FeP4 tetrahedra, edges with six FeTaP4 tetrahedra, and a faceface with one FeTa2P4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.26–2.36 Å. In the thirteenth Fe site, Fe is bonded in a 4-coordinate geometry to one Ta and four P atoms. There are a spread of Fe–P bond distances ranging from 2.16–2.23 Å. In the fourteenth Fe site, Fe is bonded to four P atoms to form a mixture of distorted corner and edge-sharing FeP4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.17–2.23 Å. In the fifteenth Fe site, Fe is bonded to two equivalent Ta and four P atoms to form distorted FeTa2P4 tetrahedra that share corners with six FeP4 tetrahedra, edges with two equivalent FeTa2P4 tetrahedra, and faces with three FeTa2P4 tetrahedra. There are a spread of Fe–P bond distances ranging from 2.20–2.27 Å. In the sixteenth Fe site, Fe is bonded to four P atoms to form a mixture of distorted corner and edge-sharing FeP4 tetrahedra. There are two shorter (2.18 Å) and two longer (2.23 Å) Fe–P bond lengths. In the seventeenth Fe site, Fe is bonded in a 5-coordinate geometry to five P atoms. There are a spread of Fe–P bond distances ranging from 2.28–2.54 Å. In the eighteenth Fe site, Fe is bonded in a 1-coordinate geometry to five P atoms. There are a spread of Fe–P bond distances ranging from 2.25–2.56 Å. In the nineteenth Fe site, Fe is bonded in a 5-coordinate geometry to five P atoms. There are a spread of Fe–P bond distances ranging from 2.27–2.52 Å. There are twelve inequivalent P sites. In the first P site, P is bonded in a 9-coordinate geometry to two equivalent Sc and seven Fe atoms. In the second P site, P is bonded in a 9-coordinate geometry to two equivalent Sc and seven Fe atoms. In the third P site, P is bonded in a 9-coordinate geometry to two equivalent Sc, two equivalent Ta, and five Fe atoms. In the fourth P site, P is bonded in a 9-coordinate geometry to two equivalent Sc and seven Fe atoms. In the fifth P site, P is bonded in a 9-coordinate geometry to two equivalent Sc and seven Fe atoms. In the sixth P site, P is bonded in a 9-coordinate geometry to two equivalent Sc and seven Fe atoms. In the seventh P site, P is bonded in a 9-coordinate geometry to two equivalent Sc, two equivalent Ta, and five Fe atoms. In the eighth P site, P is bonded in a 9-coordinate geometry to two equivalent Sc and seven Fe atoms. In the ninth P site, P is bonded in a 9-coordinate geometry to two equivalent Sc and seven Fe atoms. In the tenth P site, P is bonded in a 9-coordinate geometry to two equivalent Sc, one Ta, and six Fe atoms. In the eleventh P site, P is bonded in a 9-coordinate geometry to two equivalent Sc and seven Fe atoms. In the twelfth P site, P is bonded in a 9-coordinate geometry to two equivalent Sc and seven Fe atoms.

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Materials Data on Ta4AlN3 by Materials Project

Ta4AlN3 is MAX Phase structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Ta sites. In the first Ta site, Ta is bonded to six N atoms to form a mixture of edge and corner-sharing TaN6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.18 Å) and three longer (2.23 Å) Ta–N bond lengths. In the second Ta site, Ta is bonded in a 3-coordinate geometry to three equivalent Al and three equivalent N atoms. All Ta–Al bond lengths are 2.83 Å. All Ta–N bond lengths are 2.20 Å. Al is bonded in a 12-coordinate geometry to six equivalent Ta atoms. There are two inequivalent N sites. In the first N site, N is bonded to six equivalent Ta atoms to form a mixture of edge and corner-sharing NTa6 octahedra. The corner-sharing octahedral tilt angles are 2°. In the second N site, N is bonded to six Ta atoms to form a mixture of edge and corner-sharing NTa6 octahedra. The corner-sharing octahedral tilt angles are 2°.

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Materials Data on NaTa3N5 by Materials Project

NaTa3N5 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Na1+ is bonded in a 7-coordinate geometry to seven N3- atoms. There are a spread of Na–N bond distances ranging from 2.48–2.57 Å. There are two inequivalent Ta+4.67+ sites. In the first Ta+4.67+ site, Ta+4.67+ is bonded to six N3- atoms to form a mixture of distorted edge and corner-sharing TaN6 octahedra. The corner-sharing octahedra tilt angles range from 17–58°. There are a spread of Ta–N bond distances ranging from 2.00–2.42 Å. In the second Ta+4.67+ site, Ta+4.67+ is bonded to six N3- atoms to form a mixture of distorted edge and corner-sharing TaN6 octahedra. The corner-sharing octahedra tilt angles range from 17–25°. There are a spread of Ta–N bond distances ranging from 2.07–2.15 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded to one Na1+ and four Ta+4.67+ atoms to form a mixture of distorted edge and corner-sharing NNaTa4 trigonal bipyramids. In the second N3- site, N3- is bonded to two equivalent Na1+ and three Ta+4.67+ atoms to form distorted NNa2Ta3 trigonal bipyramids that share corners with twelve NNaTa4 trigonal bipyramids, edges with six NNaTa4 trigonal bipyramids, and a faceface with one NNa2Ta3 trigonal bipyramid. In the third N3- site, N3- is bonded to one Na1+ and four Ta+4.67+ atoms to form a mixture of distorted edge and corner-sharing NNaTa4 trigonal bipyramids.

36 MATERIALS SCIENCE↗
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Materials Data on Ta6Be15Cu8 by Materials Project

Be15Ta6Cu8 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. there are three inequivalent Be sites. In the first Be site, Be is bonded in a body-centered cubic geometry to eight equivalent Cu atoms. All Be–Cu bond lengths are 2.30 Å. In the second Be site, Be is bonded to four equivalent Be, four equivalent Ta, and four equivalent Cu atoms to form a mixture of distorted corner and face-sharing BeTa4Be4Cu4 cuboctahedra. All Be–Be bond lengths are 2.21 Å. All Be–Ta bond lengths are 2.78 Å. All Be–Cu bond lengths are 2.35 Å. In the third Be site, Be is bonded to six Be, three equivalent Ta, and three equivalent Cu atoms to form a mixture of distorted corner and face-sharing BeTa3Be6Cu3 cuboctahedra. All Be–Be bond lengths are 2.36 Å. All Be–Ta bond lengths are 2.65 Å. All Be–Cu bond lengths are 2.34 Å. Ta is bonded in a 8-coordinate geometry to eight Be, four equivalent Ta, and four equivalent Cu atoms. All Ta–Ta bond lengths are 2.94 Å. All Ta–Cu bond lengths are 2.75 Å. Cu is bonded in a 10-coordinate geometry to seven Be, three equivalent Ta, and three equivalent Cu atoms. All Cu–Cu bond lengths are 2.66 Å.

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Materials Data on Ta2TlO6 by Materials Project

Ta2TlO6 crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. there are two inequivalent Ta+4.50+ sites. In the first Ta+4.50+ site, Ta+4.50+ is bonded to six O2- atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 36–39°. There is two shorter (1.98 Å) and four longer (2.00 Å) Ta–O bond length. In the second Ta+4.50+ site, Ta+4.50+ is bonded to six O2- atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 39–40°. There are four shorter (1.99 Å) and two longer (2.01 Å) Ta–O bond lengths. Tl3+ is bonded in a hexagonal planar geometry to six O2- atoms. There are four shorter (2.73 Å) and two longer (2.74 Å) Tl–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Ta+4.50+ atoms. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Ta+4.50+ and one Tl3+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ta+4.50+ and two equivalent Tl3+ atoms.

36 MATERIALS SCIENCE↗
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Materials Data on Sr17(Ta5S21)2 by Materials Project

Sr17Ta10S42 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are seventeen inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to seven S2- atoms to form distorted SrS7 pentagonal bipyramids that share a cornercorner with one TaS6 octahedra, corners with four SrS7 pentagonal bipyramids, corners with two TaS4 tetrahedra, an edgeedge with one SrS7 pentagonal bipyramid, an edgeedge with one TaS4 tetrahedra, and a faceface with one TaS6 octahedra. The corner-sharing octahedral tilt angles are 17°. There are a spread of Sr–S bond distances ranging from 3.01–3.17 Å. In the second Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Sr–S bond distances ranging from 3.01–3.31 Å. In the third Sr2+ site, Sr2+ is bonded to seven S2- atoms to form distorted SrS7 pentagonal bipyramids that share a cornercorner with one TaS6 octahedra, corners with four SrS7 pentagonal bipyramids, corners with two TaS4 tetrahedra, an edgeedge with one SrS7 pentagonal bipyramid, an edgeedge with one TaS4 tetrahedra, and a faceface with one TaS6 octahedra. The corner-sharing octahedral tilt angles are 15°. There are a spread of Sr–S bond distances ranging from 3.02–3.15 Å. In the fourth Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Sr–S bond distances ranging from 2.99–3.29 Å. In the fifth Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sr–S bond distances ranging from 2.97–3.33 Å. In the sixth Sr2+ site, Sr2+ is bonded to seven S2- atoms to form distorted SrS7 pentagonal bipyramids that share a cornercorner with one TaS6 octahedra, corners with three SrS7 pentagonal bipyramids, corners with two TaS4 tetrahedra, an edgeedge with one TaS6 octahedra, edges with two SrS7 pentagonal bipyramids, and an edgeedge with one TaS4 tetrahedra. The corner-sharing octahedral tilt angles are 28°. There are a spread of Sr–S bond distances ranging from 3.03–3.14 Å. In the seventh Sr2+ site, Sr2+ is bonded to seven S2- atoms to form distorted SrS7 pentagonal bipyramids that share a cornercorner with one TaS6 octahedra, corners with four SrS7 pentagonal bipyramids, corners with two TaS4 tetrahedra, an edgeedge with one SrS7 pentagonal bipyramid, an edgeedge with one TaS4 tetrahedra, and a faceface with one TaS6 octahedra. The corner-sharing octahedral tilt angles are 16°. There are a spread of Sr–S bond distances ranging from 3.03–3.16 Å. In the eighth Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sr–S bond distances ranging from 2.97–3.29 Å. In the ninth Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sr–S bond distances ranging from 3.01–3.37 Å. In the tenth Sr2+ site, Sr2+ is bonded to seven S2- atoms to form distorted SrS7 pentagonal bipyramids that share a cornercorner with one TaS6 octahedra, corners with three SrS7 pentagonal bipyramids, corners with two TaS4 tetrahedra, an edgeedge with one TaS6 octahedra, edges with two SrS7 pentagonal bipyramids, and an edgeedge with one TaS4 tetrahedra. The corner-sharing octahedral tilt angles are 38°. There are a spread of Sr–S bond distances ranging from 3.04–3.19 Å. In the eleventh Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sr–S bond distances ranging from 2.99–3.37 Å. In the twelfth Sr2+ site, Sr2+ is bonded to seven S2- atoms to form distorted SrS7 pentagonal bipyramids that share a cornercorner with one TaS6 octahedra, corners with four SrS7 pentagonal bipyramids, corners with two TaS4 tetrahedra, edges with two SrS7 pentagonal bipyramids, an edgeedge with one TaS4 tetrahedra, and a faceface with one TaS6 octahedra. The corner-sharing octahedral tilt angles are 23°. There are a spread of Sr–S bond distances ranging from 3.04–3.12 Å. In the thirteenth Sr2+ site, Sr2+ is bonded to seven S2- atoms to form distorted SrS7 pentagonal bipyramids that share a cornercorner with one TaS6 octahedra, corners with four SrS7 pentagonal bipyramids, corners with two TaS4 tetrahedra, an edgeedge with one SrS7 pentagonal bipyramid, an edgeedge with one TaS4 tetrahedra, and a faceface with one TaS6 octahedra. The corner-sharing octahedral tilt angles are 18°. There are a spread of Sr–S bond distances ranging from 3.00–3.16 Å. In the fourteenth Sr2+ site, Sr2+ is bonded to seven S2- atoms to form distorted SrS7 pentagonal bipyramids that share a cornercorner with one TaS6 octahedra, corners with four SrS7 pentagonal bipyramids, corners with two TaS4 tetrahedra, an edgeedge with one TaS6 octahedra, edges with two SrS7 pentagonal bipyramids, and an edgeedge with one TaS4 tetrahedra. The corner-sharing octahedral tilt angles are 37°. There are a spread of Sr–S bond distances ranging from 3.04–3.28 Å. In the fifteenth Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sr–S bond distances ranging from 3.00–3.44 Å. In the sixteenth Sr2+ site, Sr2+ is bonded to seven S2- atoms to form distorted SrS7 pentagonal bipyramids that share a cornercorner with one TaS6 octahedra, corners with three SrS7 pentagonal bipyramids, corners with two TaS4 tetrahedra, an edgeedge with one TaS6 octahedra, edges with two SrS7 pentagonal bipyramids, and an edgeedge with one TaS4 tetrahedra. The corner-sharing octahedral tilt angles are 38°. There are a spread of Sr–S bond distances ranging from 2.99–3.27 Å. In the seventeenth Sr2+ site, Sr2+ is bonded to seven S2- atoms to form distorted SrS7 pentagonal bipyramids that share a cornercorner with one TaS6 octahedra, corners with three SrS7 pentagonal bipyramids, corners with two TaS4 tetrahedra, edges with two SrS7 pentagonal bipyramids, an edgeedge with one TaS4 tetrahedra, and a faceface with one TaS6 octahedra. The corner-sharing octahedral tilt angles are 17°. There are a spread of Sr–S bond distances ranging from 2.96–3.18 Å. There are ten inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to four S2- atoms to form TaS4 tetrahedra that share corners with four SrS7 pentagonal bipyramids and edges with two SrS7 pentagonal bipyramids. There are a spread of Ta–S bond distances ranging from 2.26–2.31 Å. In the second Ta5+ site, Ta5+ is bonded to four S2- atoms to form TaS4 tetrahedra that share corners with three SrS7 pentagonal bipyramids and an edgeedge with one SrS7 pentagonal bipyramid. There are two shorter (2.28 Å) and two longer (2.29 Å) Ta–S bond lengths. In the third Ta5+ site, Ta5+ is bonded to six S2- atoms to form distorted TaS6 octahedra that share corners with three SrS7 pentagonal bipyramids, an edgeedge with one SrS7 pentagonal bipyramid, and a faceface with one TaS6 octahedra. There are a spread of Ta–S bond distances ranging from 2.29–2.85 Å. In the fourth Ta5+ site, Ta5+ is bonded to six S2- atoms to form TaS6 octahedra that share corners with three SrS7 pentagonal bipyramids, a faceface with one TaS6 octahedra, and faces with three SrS7 pentagonal bipyramids. There are a spread of Ta–S bond distances ranging from 2.36–2.64 Å. In the fifth Ta5+ site, Ta5+ is bonded to four S2- atoms to form TaS4 tetrahedra that share corners with three SrS7 pentagonal bipyramids and edges with two SrS7 pentagonal bipyramids. There are two shorter (2.28 Å) and two longer (2.29 Å) Ta–S bond lengths. In the sixth Ta5+ site, Ta5+ is bonded to four S2- atoms to form TaS4 tetrahedra that share corners with four SrS7 pentagonal bipyramids and an edgeedge with one SrS7 pentagonal bipyramid. There are two shorter (2.28 Å) and two longer (2.29 Å) Ta–S bond lengths. In the seventh Ta5+ site, Ta5+ is bonded to six S2- atoms to form TaS6 octahedra that share corners with three SrS7 pentagonal bipyramids, edges with three SrS7 pentagonal bipyramids, and a faceface with one TaS6 octahedra. There are three shorter (2.35 Å) and three longer (2.64 Å) Ta–S bond lengths. In the eighth Ta5+ site, Ta5+ is bonded to six S2- atoms to form TaS6 octahedra that share a cornercorner with one SrS7 pentagonal bipyramid, a faceface with one TaS6 octahedra, and faces with three SrS7 pentagonal bipyramids. There are a spread of Ta–S bond distances ranging from 2.36–2.63 Å. In the ninth Ta5+ site, Ta5+ is bonded to four S2- atoms to form TaS4 tetrahedra that share corners with three SrS7 pentagonal bipyramids and edges with two SrS7 pentagonal bipyramids. There are a spread of Ta–S bond distances ranging from 2.26–2.30 Å. In the tenth Ta5+ site, Ta5+ is bonded to four S2- atoms to form TaS4 tetrahedra that share corners with three SrS7 pentagonal bipyramids and edges with two SrS7 pentagonal bipyramids. There are one shorter (2.25 Å) and three longer (2.30 Å) Ta–S bond lengths. There are forty-two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 5-coordinate geometry to four Sr2+ and one Ta5+ atom. In the second S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Sr2+ and one Ta5+ atom. In the third S2- site, S2- is bonded to three Sr2+ and one Ta5+ atom to form distorted corner-sharing SSr3Ta tetrahedra. In the fourth S2- site, S2- is bonded in a rectangular see-saw-like geometry to three Sr2+ and one Ta5+ atom. In the fifth S2- site, S2- is bonded to three Sr2+ and one Ta5+ atom to form distorted SSr3Ta tetrahedra that share corners with two SSr3Ta2 square pyramids and corners with two SSr3Ta trigonal pyramids. In the sixth S2- site, S2- is bonded in a 3-coordinate geometry to two Sr2+ and one Ta5+ atom. In the seventh S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Sr2+ and one Ta5+ atom. In the eighth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Sr2+ and one Ta5+ atom. In the ninth S2- site, S2- is bonded in a rectangular see-saw-like geometry to two Sr2+ and two Ta5+ atoms. In the tenth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Sr2+ and one Ta5+ atom. In the eleventh S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Sr2+ and one Ta5+ atom. In the twelfth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Sr2+ and one Ta5+ atom. In the thirteenth S2- site, S2- is bonded in a rectangular see-saw-like geometry to two Sr2+ and two Ta5+ atoms. In the fourteenth S2- site, S2- is bonded in a distorted square co-planar geometry to three Sr2+ and one Ta5+ atom. In the fifteenth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Sr2+ and one Ta5+ atom. In the sixteenth S2- site, S2- is bonded to three Sr2+ and one Ta5+ atom to form distorted SSr3Ta tetrahedra that share corners with two SSr3Ta2 square pyramids and a cornercorner with one SSr3Ta trigonal pyramid. In the seventeenth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Sr2+ and one Ta5+ atom. In the eighteenth S2- site, S2- is bonded to three Sr2+ and two Ta5+ atoms to form distorted corner-sharing SSr3Ta2 square pyramids. In the nineteenth S2- site, S2- is bonded in a 5-coordinate geometry to four Sr2+ and one Ta5+ atom. In the twentieth S2- site, S2- is bonded to three Sr2+ and one Ta5+ atom to form distorted SSr3Ta trigonal pyramids that share a cornercorner with one SSr3Ta2 square pyramid, corners with three SSr3Ta tetrahedra, edges with two SSr3Ta2 square pyramids, and an edgeedge with one SSr3Ta trigonal pyramid. In the twenty-first S2- site, S2- is bonded to three Sr2+ and one Ta5+ atom to form distorted SSr3Ta tetrahedra that share corners with two SSr3Ta2 square pyramids and a cornercorner with one SSr3Ta trigonal pyramid. In the twenty-second S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Sr2+ and one Ta5+ atom. In the twenty-third S2- site, S2- is bonded in a distorted rectangular see-saw-

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr17(Ta5S21)2 by Materials Project

Sr17Ta10S42 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are seventeen inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to seven S2- atoms to form distorted SrS7 pentagonal bipyramids that share a cornercorner with one TaS6 octahedra, corners with three SrS7 pentagonal bipyramids, corners with two TaS4 tetrahedra, an edgeedge with one SrS7 pentagonal bipyramid, an edgeedge with one TaS4 tetrahedra, and a faceface with one TaS6 octahedra. The corner-sharing octahedral tilt angles are 17°. There are a spread of Sr–S bond distances ranging from 2.98–3.17 Å. In the second Sr2+ site, Sr2+ is bonded to seven S2- atoms to form distorted SrS7 pentagonal bipyramids that share a cornercorner with one TaS6 octahedra, corners with three SrS7 pentagonal bipyramids, corners with two TaS4 tetrahedra, an edgeedge with one TaS6 octahedra, an edgeedge with one SrS7 pentagonal bipyramid, and an edgeedge with one TaS4 tetrahedra. The corner-sharing octahedral tilt angles are 38°. There are a spread of Sr–S bond distances ranging from 3.05–3.29 Å. In the third Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sr–S bond distances ranging from 2.95–3.37 Å. In the fourth Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Sr–S bond distances ranging from 3.01–3.21 Å. In the fifth Sr2+ site, Sr2+ is bonded to seven S2- atoms to form distorted SrS7 pentagonal bipyramids that share a cornercorner with one TaS6 octahedra, corners with three SrS7 pentagonal bipyramids, corners with two TaS4 tetrahedra, an edgeedge with one TaS6 octahedra, an edgeedge with one SrS7 pentagonal bipyramid, and an edgeedge with one TaS4 tetrahedra. The corner-sharing octahedral tilt angles are 36°. There are a spread of Sr–S bond distances ranging from 3.01–3.18 Å. In the sixth Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sr–S bond distances ranging from 2.96–3.30 Å. In the seventh Sr2+ site, Sr2+ is bonded to seven S2- atoms to form distorted SrS7 pentagonal bipyramids that share a cornercorner with one TaS6 octahedra, corners with three SrS7 pentagonal bipyramids, corners with two TaS4 tetrahedra, an edgeedge with one SrS7 pentagonal bipyramid, an edgeedge with one TaS4 tetrahedra, and a faceface with one TaS6 octahedra. The corner-sharing octahedral tilt angles are 18°. There are a spread of Sr–S bond distances ranging from 2.99–3.14 Å. In the eighth Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sr–S bond distances ranging from 2.98–3.28 Å. In the ninth Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sr–S bond distances ranging from 3.00–3.36 Å. In the tenth Sr2+ site, Sr2+ is bonded to seven S2- atoms to form distorted SrS7 pentagonal bipyramids that share a cornercorner with one TaS6 octahedra, corners with three SrS7 pentagonal bipyramids, corners with two TaS4 tetrahedra, an edgeedge with one TaS6 octahedra, edges with two SrS7 pentagonal bipyramids, and an edgeedge with one TaS4 tetrahedra. The corner-sharing octahedral tilt angles are 38°. There are a spread of Sr–S bond distances ranging from 3.05–3.21 Å. In the eleventh Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sr–S bond distances ranging from 3.00–3.38 Å. In the twelfth Sr2+ site, Sr2+ is bonded to seven S2- atoms to form distorted SrS7 pentagonal bipyramids that share a cornercorner with one TaS6 octahedra, corners with three SrS7 pentagonal bipyramids, corners with two TaS4 tetrahedra, an edgeedge with one SrS7 pentagonal bipyramid, an edgeedge with one TaS4 tetrahedra, and a faceface with one TaS6 octahedra. The corner-sharing octahedral tilt angles are 19°. There are a spread of Sr–S bond distances ranging from 3.00–3.14 Å. In the thirteenth Sr2+ site, Sr2+ is bonded to seven S2- atoms to form distorted SrS7 pentagonal bipyramids that share a cornercorner with one TaS6 octahedra, corners with three SrS7 pentagonal bipyramids, corners with two TaS4 tetrahedra, edges with two SrS7 pentagonal bipyramids, an edgeedge with one TaS4 tetrahedra, and a faceface with one TaS6 octahedra. The corner-sharing octahedral tilt angles are 18°. There are a spread of Sr–S bond distances ranging from 2.99–3.18 Å. In the fourteenth Sr2+ site, Sr2+ is bonded to seven S2- atoms to form distorted SrS7 pentagonal bipyramids that share a cornercorner with one TaS6 octahedra, corners with three SrS7 pentagonal bipyramids, corners with two TaS4 tetrahedra, an edgeedge with one TaS6 octahedra, edges with two SrS7 pentagonal bipyramids, and an edgeedge with one TaS4 tetrahedra. The corner-sharing octahedral tilt angles are 42°. There are a spread of Sr–S bond distances ranging from 3.03–3.21 Å. In the fifteenth Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sr–S bond distances ranging from 2.98–3.49 Å. In the sixteenth Sr2+ site, Sr2+ is bonded to seven S2- atoms to form distorted SrS7 pentagonal bipyramids that share a cornercorner with one TaS6 octahedra, corners with four SrS7 pentagonal bipyramids, corners with two TaS4 tetrahedra, an edgeedge with one SrS7 pentagonal bipyramid, an edgeedge with one TaS4 tetrahedra, and a faceface with one TaS6 octahedra. The corner-sharing octahedral tilt angles are 17°. There are a spread of Sr–S bond distances ranging from 3.00–3.18 Å. In the seventeenth Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Sr–S bond distances ranging from 3.01–3.29 Å. There are ten inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to four S2- atoms to form TaS4 tetrahedra that share corners with three SrS7 pentagonal bipyramids and edges with two SrS7 pentagonal bipyramids. There are one shorter (2.28 Å) and three longer (2.29 Å) Ta–S bond lengths. In the second Ta5+ site, Ta5+ is bonded to four S2- atoms to form TaS4 tetrahedra that share corners with three SrS7 pentagonal bipyramids and an edgeedge with one SrS7 pentagonal bipyramid. There are a spread of Ta–S bond distances ranging from 2.26–2.31 Å. In the third Ta5+ site, Ta5+ is bonded to six S2- atoms to form TaS6 octahedra that share corners with two SrS7 pentagonal bipyramids, an edgeedge with one SrS7 pentagonal bipyramid, and a faceface with one TaS6 octahedra. There are a spread of Ta–S bond distances ranging from 2.37–2.62 Å. In the fourth Ta5+ site, Ta5+ is bonded to six S2- atoms to form distorted TaS6 octahedra that share corners with three SrS7 pentagonal bipyramids, a faceface with one TaS6 octahedra, and faces with two SrS7 pentagonal bipyramids. There are a spread of Ta–S bond distances ranging from 2.31–2.74 Å. In the fifth Ta5+ site, Ta5+ is bonded to four S2- atoms to form TaS4 tetrahedra that share corners with two SrS7 pentagonal bipyramids and edges with two SrS7 pentagonal bipyramids. There are a spread of Ta–S bond distances ranging from 2.26–2.30 Å. In the sixth Ta5+ site, Ta5+ is bonded to four S2- atoms to form TaS4 tetrahedra that share corners with three SrS7 pentagonal bipyramids and an edgeedge with one SrS7 pentagonal bipyramid. There are two shorter (2.28 Å) and two longer (2.29 Å) Ta–S bond lengths. In the seventh Ta5+ site, Ta5+ is bonded to six S2- atoms to form TaS6 octahedra that share corners with three SrS7 pentagonal bipyramids, edges with three SrS7 pentagonal bipyramids, and a faceface with one TaS6 octahedra. There are a spread of Ta–S bond distances ranging from 2.34–2.67 Å. In the eighth Ta5+ site, Ta5+ is bonded to six S2- atoms to form TaS6 octahedra that share a cornercorner with one SrS7 pentagonal bipyramid, a faceface with one TaS6 octahedra, and faces with three SrS7 pentagonal bipyramids. There are a spread of Ta–S bond distances ranging from 2.36–2.61 Å. In the ninth Ta5+ site, Ta5+ is bonded to four S2- atoms to form TaS4 tetrahedra that share corners with four SrS7 pentagonal bipyramids and edges with two SrS7 pentagonal bipyramids. There are two shorter (2.28 Å) and two longer (2.29 Å) Ta–S bond lengths. In the tenth Ta5+ site, Ta5+ is bonded to four S2- atoms to form TaS4 tetrahedra that share corners with three SrS7 pentagonal bipyramids and an edgeedge with one SrS7 pentagonal bipyramid. There are one shorter (2.25 Å) and three longer (2.30 Å) Ta–S bond lengths. There are forty-two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 1-coordinate geometry to four Sr2+ and one Ta5+ atom. In the second S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Sr2+ and one Ta5+ atom. In the third S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Sr2+ and one Ta5+ atom. In the fourth S2- site, S2- is bonded in a distorted trigonal non-coplanar geometry to two Sr2+ and one Ta5+ atom. In the fifth S2- site, S2- is bonded to three Sr2+ and one Ta5+ atom to form distorted SSr3Ta trigonal pyramids that share a cornercorner with one SSr3Ta2 square pyramid, corners with three SSr3Ta tetrahedra, an edgeedge with one SSr3Ta2 square pyramid, and an edgeedge with one SSr3Ta trigonal pyramid. In the sixth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Sr2+ and one Ta5+ atom. In the seventh S2- site, S2- is bonded to three Sr2+ and one Ta5+ atom to form distorted SSr3Ta tetrahedra that share corners with two SSr3Ta2 square pyramids and corners with three SSr3Ta trigonal pyramids. In the eighth S2- site, S2- is bonded in a 3-coordinate geometry to two Sr2+ and one Ta5+ atom. In the ninth S2- site, S2- is bonded to three Sr2+ and one Ta5+ atom to form distorted SSr3Ta trigonal pyramids that share corners with two SSr3Ta tetrahedra, a cornercorner with one SSr4Ta trigonal bipyramid, edges with two SSr3Ta2 square pyramids, and an edgeedge with one SSr3Ta trigonal pyramid. In the tenth S2- site, S2- is bonded in a rectangular see-saw-like geometry to two Sr2+ and two Ta5+ atoms. In the eleventh S2- site, S2- is bonded in a 1-coordinate geometry to two Sr2+ and one Ta5+ atom. In the twelfth S2- site, S2- is bonded in a 3-coordinate geometry to two Sr2+ and one Ta5+ atom. In the thirteenth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Sr2+ and one Ta5+ atom. In the fourteenth S2- site, S2- is bonded to three Sr2+ and two Ta5+ atoms to form SSr3Ta2 square pyramids that share corners with three SSr3Ta tetrahedra, a cornercorner with one SSr3Ta trigonal pyramid, an edgeedge with one SSr3Ta trigonal pyramid, a faceface with one SSr3Ta2 square pyramid, and a faceface with one SSr4Ta trigonal bipyramid. In the fifteenth S2- site, S2- is bonded in a 4-coordinate geometry to three Sr2+ and one Ta5+ atom. In the sixteenth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Sr2+ and one Ta5+ atom. In the seventeenth S2- site, S2- is bonded to three Sr2+ and one Ta5+ atom to form distorted SSr3Ta tetrahedra that share corners with three SSr3Ta2 square pyramids, a cornercorner with one SSr4Ta trigonal bipyramid, and corners with three SSr3Ta trigonal pyramids. In the eighteenth S2- site, S2- is bonded to three Sr2+ and two Ta5+ atoms to form SSr3Ta2 square pyramids that share corners with three SSr3Ta tetrahedra, edges with two SSr3Ta trigonal pyramids, a faceface with one SSr3Ta2 square pyramid, and a faceface with one SSr4Ta trigonal bipyramid. In the nineteenth S2- site, S2- is bonded in a 4-coordinate geometry to three Sr2+ and one Ta5+ atom. In the twentieth S2- site, S2- is bonded to three Sr2+ and one Ta5+ atom to form distorted SSr3Ta trigonal pyramids that share a cornercorner with one SSr3Ta2 square pyramid, corners with three SSr3Ta tetrahedra, edges with two SSr3Ta2 square pyramids, and edges with two SSr3Ta

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta3AlC2 by Materials Project

Ta3AlC2 is MAX Phase-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Ta sites. In the first Ta site, Ta is bonded in a 3-coordinate geometry to three equivalent Al and three equivalent C atoms. All Ta–Al bond lengths are 2.86 Å. All Ta–C bond lengths are 2.20 Å. In the second Ta site, Ta is bonded to six equivalent C atoms to form edge-sharing TaC6 octahedra. All Ta–C bond lengths are 2.22 Å. Al is bonded in a 12-coordinate geometry to six equivalent Ta atoms. C is bonded to six Ta atoms to form a mixture of edge and corner-sharing CTa6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗