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DOE OSTI2020

Materials Data on Ta10Al6B by Materials Project

Ta10Al6B crystallizes in the trigonal P-31m space group. The structure is three-dimensional. there are three inequivalent Ta sites. In the first Ta site, Ta is bonded in a 8-coordinate geometry to two equivalent Ta and six equivalent Al atoms. Both Ta–Ta bond lengths are 2.65 Å. All Ta–Al bond lengths are 2.73 Å. In the second Ta site, Ta is bonded in a 8-coordinate geometry to two equivalent Ta and six equivalent Al atoms. All Ta–Al bond lengths are 2.74 Å. In the third Ta site, Ta is bonded in a distorted single-bond geometry to five equivalent Al and one B atom. There are a spread of Ta–Al bond distances ranging from 2.74–2.96 Å. The Ta–B bond length is 2.32 Å. Al is bonded in a 9-coordinate geometry to nine Ta atoms. B is bonded in an octahedral geometry to six equivalent Ta atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaPd by Materials Project

PdTa crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent Ta sites. In the first Ta site, Ta is bonded to six equivalent Ta and six Pd atoms to form distorted TaTa6Pd6 cuboctahedra that share corners with twelve TaTa6Pd6 cuboctahedra, edges with twelve TaTa6Pd6 cuboctahedra, edges with twelve PdTa6Pd6 cuboctahedra, faces with six equivalent TaTa6Pd6 cuboctahedra, and faces with twelve PdTa6Pd6 cuboctahedra. All Ta–Ta bond lengths are 2.88 Å. All Ta–Pd bond lengths are 2.86 Å. In the second Ta site, Ta is bonded to ten equivalent Ta and six Pd atoms to form distorted TaTa10Pd6 cuboctahedra that share corners with ten PdTa6Pd6 cuboctahedra, corners with twelve TaTa6Pd6 cuboctahedra, edges with eight PdTa6Pd6 cuboctahedra, edges with sixteen TaTa6Pd6 cuboctahedra, faces with sixteen equivalent TaTa10Pd6 cuboctahedra, and faces with eighteen PdTa6Pd6 cuboctahedra. There are a spread of Ta–Ta bond distances ranging from 2.88–5.75 Å. All Ta–Pd bond lengths are 2.86 Å. There are three inequivalent Pd sites. In the first Pd site, Pd is bonded to six equivalent Ta and six equivalent Pd atoms to form distorted PdTa6Pd6 cuboctahedra that share corners with twelve PdTa6Pd6 cuboctahedra, edges with twelve equivalent TaTa6Pd6 cuboctahedra, edges with twelve PdTa6Pd6 cuboctahedra, faces with six equivalent PdTa6Pd6 cuboctahedra, and faces with twelve equivalent TaTa6Pd6 cuboctahedra. All Pd–Pd bond lengths are 2.88 Å. In the second Pd site, Pd is bonded to six Ta and six equivalent Pd atoms to form distorted PdTa6Pd6 cuboctahedra that share corners with five equivalent TaTa10Pd6 cuboctahedra, corners with twelve PdTa6Pd6 cuboctahedra, edges with ten TaTa6Pd6 cuboctahedra, edges with twelve PdTa6Pd6 cuboctahedra, faces with six equivalent PdTa6Pd6 cuboctahedra, and faces with fifteen TaTa6Pd6 cuboctahedra. All Pd–Ta bond lengths are 2.86 Å. All Pd–Pd bond lengths are 2.88 Å. In the third Pd site, Pd is bonded to six Ta and six equivalent Pd atoms to form distorted PdTa6Pd6 cuboctahedra that share corners with five equivalent TaTa10Pd6 cuboctahedra, corners with twelve PdTa6Pd6 cuboctahedra, edges with ten TaTa6Pd6 cuboctahedra, edges with twelve PdTa6Pd6 cuboctahedra, faces with six equivalent PdTa6Pd6 cuboctahedra, and faces with fifteen TaTa6Pd6 cuboctahedra. All Pd–Pd bond lengths are 2.88 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta9(CoS3)2 by Materials Project

Ta9(CoS3)2 crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. there are three inequivalent Ta sites. In the first Ta site, Ta is bonded to two equivalent Co and three S atoms to form a mixture of distorted edge and corner-sharing TaCo2S3 trigonal bipyramids. Both Ta–Co bond lengths are 2.44 Å. There are one shorter (2.39 Å) and two longer (2.52 Å) Ta–S bond lengths. In the second Ta site, Ta is bonded in a 5-coordinate geometry to two equivalent Co and three S atoms. Both Ta–Co bond lengths are 2.56 Å. There are one shorter (2.43 Å) and two longer (2.56 Å) Ta–S bond lengths. In the third Ta site, Ta is bonded in a 3-coordinate geometry to three S atoms. There are a spread of Ta–S bond distances ranging from 2.50–2.55 Å. Co is bonded in a 6-coordinate geometry to six Ta atoms. There are three inequivalent S sites. In the first S site, S is bonded in a distorted pentagonal planar geometry to five Ta atoms. In the second S site, S is bonded in a distorted rectangular see-saw-like geometry to four Ta atoms. In the third S site, S is bonded in a 4-coordinate geometry to four Ta atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta9(FeS3)2 by Materials Project

Ta9(FeS3)2 crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. there are three inequivalent Ta sites. In the first Ta site, Ta is bonded in a 5-coordinate geometry to two equivalent Fe and three S atoms. Both Ta–Fe bond lengths are 2.57 Å. There are one shorter (2.42 Å) and two longer (2.59 Å) Ta–S bond lengths. In the second Ta site, Ta is bonded to two equivalent Fe and three S atoms to form a mixture of distorted corner and edge-sharing TaFe2S3 trigonal bipyramids. Both Ta–Fe bond lengths are 2.42 Å. There are one shorter (2.44 Å) and two longer (2.54 Å) Ta–S bond lengths. In the third Ta site, Ta is bonded in a 3-coordinate geometry to three S atoms. There are one shorter (2.51 Å) and two longer (2.52 Å) Ta–S bond lengths. Fe is bonded in a 6-coordinate geometry to six Ta atoms. There are three inequivalent S sites. In the first S site, S is bonded in a distorted pentagonal planar geometry to five Ta atoms. In the second S site, S is bonded in a distorted rectangular see-saw-like geometry to four Ta atoms. In the third S site, S is bonded in a 4-coordinate geometry to four Ta atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Rb2Ta2Si2O11 by Materials Project

Rb2Ta2Si2O11 crystallizes in the tetragonal P4_122 space group. The structure is three-dimensional. there are three inequivalent Rb sites. In the first Rb site, Rb is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Rb–O bond distances ranging from 3.02–3.50 Å. In the second Rb site, Rb is bonded in a 1-coordinate geometry to three O atoms. There are a spread of Rb–O bond distances ranging from 2.76–3.18 Å. In the third Rb site, Rb is bonded in a 10-coordinate geometry to ten O atoms. There are a spread of Rb–O bond distances ranging from 2.99–3.47 Å. There are two inequivalent Ta sites. In the first Ta site, Ta is bonded to six O atoms to form TaO6 octahedra that share corners with four TaO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 36–44°. There are a spread of Ta–O bond distances ranging from 1.94–2.05 Å. In the second Ta site, Ta is bonded to six O atoms to form TaO6 octahedra that share corners with four TaO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 36–44°. There are a spread of Ta–O bond distances ranging from 1.93–2.08 Å. There are two inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two TaO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 41–43°. There are a spread of Si–O bond distances ranging from 1.63–1.65 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two TaO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 41–43°. There is three shorter (1.63 Å) and one longer (1.65 Å) Si–O bond length. There are twelve inequivalent O sites. In the first O site, O is bonded in a distorted bent 150 degrees geometry to one Rb and two Si atoms. In the second O site, O is bonded in a distorted bent 150 degrees geometry to one Ta and one Si atom. In the third O site, O is bonded in a distorted bent 150 degrees geometry to one Rb and two equivalent Ta atoms. In the fourth O site, O is bonded in a distorted linear geometry to one Rb and two Si atoms. In the fifth O site, O is bonded in a distorted see-saw-like geometry to three Rb and one O atom. The O–O bond length is 1.24 Å. In the sixth O site, O is bonded in a 2-coordinate geometry to one Rb and two Ta atoms. In the seventh O site, O is bonded in a 2-coordinate geometry to one Rb, one Ta, and one Si atom. In the eighth O site, O is bonded in a 2-coordinate geometry to one Rb, one Ta, and one Si atom. In the ninth O site, O is bonded in a distorted bent 150 degrees geometry to one Ta and one Si atom. In the tenth O site, O is bonded in a distorted bent 150 degrees geometry to one Rb and two Ta atoms. In the eleventh O site, O is bonded in a bent 150 degrees geometry to one Rb and two equivalent Ta atoms. In the twelfth O site, O is bonded in a 2-coordinate geometry to one Rb and two Ta atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta4(Pd3Rh)3 by Materials Project

Ta4(RhPd3)3 is beta Cu3Ti-derived structured and crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. there are three inequivalent Ta sites. In the first Ta site, Ta is bonded to six Rh and six equivalent Pd atoms to form TaPd6Rh6 cuboctahedra that share corners with twelve TaPd6Rh6 cuboctahedra, edges with eighteen PdTa4Pd8 cuboctahedra, faces with six equivalent TaPd9Rh3 cuboctahedra, and faces with six equivalent PdTa4Pd6Rh2 cuboctahedra. All Ta–Rh bond lengths are 2.79 Å. All Ta–Pd bond lengths are 2.80 Å. In the second Ta site, Ta is bonded to twelve Pd atoms to form TaPd12 cuboctahedra that share corners with twelve TaPd6Rh6 cuboctahedra, edges with eighteen PdTa4Pd8 cuboctahedra, faces with six equivalent TaPd9Rh3 cuboctahedra, and faces with twelve PdTa4Pd8 cuboctahedra. There are six shorter (2.79 Å) and six longer (2.80 Å) Ta–Pd bond lengths. In the third Ta site, Ta is bonded to three Rh and nine Pd atoms to form TaPd9Rh3 cuboctahedra that share corners with six equivalent TaPd9Rh3 cuboctahedra, corners with twelve equivalent PdTa4Pd6Rh2 cuboctahedra, edges with twelve PdTa4Pd8 cuboctahedra, faces with eight TaPd6Rh6 cuboctahedra, and faces with nine PdTa4Pd8 cuboctahedra. All Ta–Rh bond lengths are 2.68 Å. There are six shorter (2.80 Å) and three longer (2.93 Å) Ta–Pd bond lengths. There are two inequivalent Rh sites. In the first Rh site, Rh is bonded in a 12-coordinate geometry to four Ta, four Rh, and four equivalent Pd atoms. There are two shorter (2.78 Å) and two longer (2.81 Å) Rh–Rh bond lengths. All Rh–Pd bond lengths are 2.79 Å. In the second Rh site, Rh is bonded in a 12-coordinate geometry to four Ta, four equivalent Rh, and four equivalent Pd atoms. All Rh–Pd bond lengths are 2.79 Å. There are two inequivalent Pd sites. In the first Pd site, Pd is bonded to four Ta and eight Pd atoms to form distorted PdTa4Pd8 cuboctahedra that share corners with six equivalent PdTa4Pd8 cuboctahedra, edges with eight TaPd6Rh6 cuboctahedra, edges with twelve PdTa4Pd8 cuboctahedra, faces with four TaPd12 cuboctahedra, and faces with fourteen PdTa4Pd8 cuboctahedra. There are two shorter (2.78 Å) and six longer (2.81 Å) Pd–Pd bond lengths. In the second Pd site, Pd is bonded to four Ta, two Rh, and six Pd atoms to form distorted PdTa4Pd6Rh2 cuboctahedra that share corners with four equivalent TaPd9Rh3 cuboctahedra, corners with fourteen equivalent PdTa4Pd6Rh2 cuboctahedra, edges with six TaPd6Rh6 cuboctahedra, edges with eight PdTa4Pd8 cuboctahedra, faces with four TaPd6Rh6 cuboctahedra, and faces with eleven PdTa4Pd8 cuboctahedra. There are two shorter (2.77 Å) and two longer (2.81 Å) Pd–Pd bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta2Ti2Co2C by Materials Project

Ti2Ta2Co2C crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. there are two inequivalent Ti sites. In the first Ti site, Ti is bonded in a 6-coordinate geometry to six Co atoms. All Ti–Co bond lengths are 2.50 Å. In the second Ti site, Ti is bonded in a distorted bent 150 degrees geometry to four Co and two equivalent C atoms. There are two shorter (2.72 Å) and two longer (3.00 Å) Ti–Co bond lengths. Both Ti–C bond lengths are 2.13 Å. There are three inequivalent Ta sites. In the first Ta site, Ta is bonded in a distorted bent 150 degrees geometry to four Co and two equivalent C atoms. There are two shorter (2.73 Å) and two longer (2.94 Å) Ta–Co bond lengths. Both Ta–C bond lengths are 2.17 Å. In the second Ta site, Ta is bonded in a distorted bent 150 degrees geometry to four Co and two equivalent C atoms. There are two shorter (2.72 Å) and two longer (2.97 Å) Ta–Co bond lengths. Both Ta–C bond lengths are 2.19 Å. In the third Ta site, Ta is bonded in a distorted bent 150 degrees geometry to four Co and two equivalent C atoms. There are two shorter (2.75 Å) and two longer (2.96 Å) Ta–Co bond lengths. Both Ta–C bond lengths are 2.17 Å. There are two inequivalent Co sites. In the first Co site, Co is bonded in a 12-coordinate geometry to five Ti, four Ta, and three equivalent Co atoms. There are one shorter (2.70 Å) and two longer (2.73 Å) Co–Co bond lengths. In the second Co site, Co is bonded in a 12-coordinate geometry to five Ti, four Ta, and three equivalent Co atoms. All Co–Co bond lengths are 2.74 Å. C is bonded to two equivalent Ti and four Ta atoms to form corner-sharing CTa4Ti2 octahedra. The corner-sharing octahedra tilt angles range from 37–41°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta3(CuS3)2 by Materials Project

Ta3(CuS3)2 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. there are three inequivalent Ta+3.33+ sites. In the first Ta+3.33+ site, Ta+3.33+ is bonded to six S2- atoms to form distorted TaS6 pentagonal pyramids that share corners with six CuS4 trigonal pyramids, edges with six TaS6 pentagonal pyramids, and a faceface with one CuS4 trigonal pyramid. There are a spread of Ta–S bond distances ranging from 2.45–2.54 Å. In the second Ta+3.33+ site, Ta+3.33+ is bonded to six S2- atoms to form distorted TaS6 pentagonal pyramids that share corners with seven CuS4 trigonal pyramids and edges with six TaS6 pentagonal pyramids. There are a spread of Ta–S bond distances ranging from 2.47–2.50 Å. In the third Ta+3.33+ site, Ta+3.33+ is bonded to six S2- atoms to form distorted TaS6 pentagonal pyramids that share corners with five CuS4 trigonal pyramids, edges with six TaS6 pentagonal pyramids, and a faceface with one CuS4 trigonal pyramid. There are a spread of Ta–S bond distances ranging from 2.47–2.54 Å. There are two inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded to four S2- atoms to form distorted CuS4 trigonal pyramids that share corners with nine TaS6 pentagonal pyramids, corners with two equivalent CuS4 trigonal pyramids, and a faceface with one TaS6 pentagonal pyramid. There are a spread of Cu–S bond distances ranging from 2.23–2.33 Å. In the second Cu1+ site, Cu1+ is bonded to four S2- atoms to form distorted CuS4 trigonal pyramids that share corners with nine TaS6 pentagonal pyramids, corners with two equivalent CuS4 trigonal pyramids, and a faceface with one TaS6 pentagonal pyramid. There are a spread of Cu–S bond distances ranging from 2.23–2.32 Å. There are six inequivalent S2- sites. In the first S2- site, S2- is bonded in a 5-coordinate geometry to three Ta+3.33+ and two equivalent Cu1+ atoms. In the second S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Ta+3.33+ and one Cu1+ atom. In the third S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Ta+3.33+ and one Cu1+ atom. In the fourth S2- site, S2- is bonded in a rectangular see-saw-like geometry to three Ta+3.33+ and one Cu1+ atom. In the fifth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Ta+3.33+ and one Cu1+ atom. In the sixth S2- site, S2- is bonded in a 5-coordinate geometry to three Ta+3.33+ and two equivalent Cu1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta3MoS8 by Materials Project

TaMoS4(TaS2)2 is Molybdenite-derived structured and crystallizes in the monoclinic Cm space group. The structure is two-dimensional and consists of two TaMoS4 sheets oriented in the (1, 0, 0) direction and two TaS2 sheets oriented in the (1, 0, 0) direction. In each TaMoS4 sheet, Ta+4.33+ is bonded to six S2- atoms to form distorted TaS6 pentagonal pyramids that share edges with two equivalent TaS6 pentagonal pyramids and edges with four equivalent MoS6 pentagonal pyramids. There are four shorter (2.47 Å) and two longer (2.48 Å) Ta–S bond lengths. Mo3+ is bonded to six S2- atoms to form distorted MoS6 pentagonal pyramids that share edges with two equivalent MoS6 pentagonal pyramids and edges with four equivalent TaS6 pentagonal pyramids. There are two shorter (2.44 Å) and four longer (2.45 Å) Mo–S bond lengths. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a 3-coordinate geometry to one Ta+4.33+ and two equivalent Mo3+ atoms. In the second S2- site, S2- is bonded in a 3-coordinate geometry to two equivalent Ta+4.33+ and one Mo3+ atom. In the third S2- site, S2- is bonded in a 3-coordinate geometry to two equivalent Ta+4.33+ and one Mo3+ atom. In each TaS2 sheet, there are two inequivalent Ta+4.33+ sites. In the first Ta+4.33+ site, Ta+4.33+ is bonded to six S2- atoms to form distorted edge-sharing TaS6 pentagonal pyramids. There are four shorter (2.48 Å) and two longer (2.49 Å) Ta–S bond lengths. In the second Ta+4.33+ site, Ta+4.33+ is bonded to six S2- atoms to form distorted edge-sharing TaS6 pentagonal pyramids. All Ta–S bond lengths are 2.48 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 3-coordinate geometry to three Ta+4.33+ atoms. In the second S2- site, S2- is bonded in a 3-coordinate geometry to three Ta+4.33+ atoms. In the third S2- site, S2- is bonded in a 3-coordinate geometry to three Ta+4.33+ atoms. In the fourth S2- site, S2- is bonded in a 3-coordinate geometry to three Ta+4.33+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta2Ti2Ni2C by Materials Project

Ti2Ta2Ni2C crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. there are two inequivalent Ti sites. In the first Ti site, Ti is bonded in a 6-coordinate geometry to six Ni atoms. There are three shorter (2.49 Å) and three longer (2.51 Å) Ti–Ni bond lengths. In the second Ti site, Ti is bonded in a distorted bent 150 degrees geometry to four Ni and two equivalent C atoms. There are two shorter (2.66 Å) and two longer (3.03 Å) Ti–Ni bond lengths. Both Ti–C bond lengths are 2.12 Å. There are three inequivalent Ta sites. In the first Ta site, Ta is bonded in a distorted bent 150 degrees geometry to four Ni and two equivalent C atoms. There are two shorter (2.68 Å) and two longer (3.00 Å) Ta–Ni bond lengths. Both Ta–C bond lengths are 2.16 Å. In the second Ta site, Ta is bonded in a distorted bent 150 degrees geometry to two equivalent Ni and two equivalent C atoms. Both Ta–Ni bond lengths are 2.77 Å. Both Ta–C bond lengths are 2.17 Å. In the third Ta site, Ta is bonded in a distorted bent 150 degrees geometry to two equivalent Ni and two equivalent C atoms. Both Ta–Ni bond lengths are 2.78 Å. Both Ta–C bond lengths are 2.15 Å. There are two inequivalent Ni sites. In the first Ni site, Ni is bonded in a 12-coordinate geometry to five Ti, four Ta, and three equivalent Ni atoms. There are two shorter (2.61 Å) and one longer (2.62 Å) Ni–Ni bond lengths. In the second Ni site, Ni is bonded in a 12-coordinate geometry to five Ti and one Ta atom. C is bonded to two equivalent Ti and four Ta atoms to form corner-sharing CTa4Ti2 octahedra. The corner-sharing octahedra tilt angles range from 35–39°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NdTa3O9 by Materials Project

NdTa3O9 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are six inequivalent Nd3+ sites. In the first Nd3+ site, Nd3+ is bonded to twelve O2- atoms to form NdO12 cuboctahedra that share faces with two NdO12 cuboctahedra and faces with eight TaO6 octahedra. There are a spread of Nd–O bond distances ranging from 2.57–2.73 Å. In the second Nd3+ site, Nd3+ is bonded to twelve O2- atoms to form NdO12 cuboctahedra that share faces with two equivalent NdO12 cuboctahedra and faces with eight TaO6 octahedra. There are a spread of Nd–O bond distances ranging from 2.60–2.72 Å. In the third Nd3+ site, Nd3+ is bonded to twelve O2- atoms to form NdO12 cuboctahedra that share faces with two NdO12 cuboctahedra and faces with eight TaO6 octahedra. There are a spread of Nd–O bond distances ranging from 2.56–2.74 Å. In the fourth Nd3+ site, Nd3+ is bonded to twelve O2- atoms to form NdO12 cuboctahedra that share faces with two equivalent NdO12 cuboctahedra and faces with eight TaO6 octahedra. There are a spread of Nd–O bond distances ranging from 2.59–2.71 Å. In the fifth Nd3+ site, Nd3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Nd–O bond distances ranging from 2.45–2.94 Å. In the sixth Nd3+ site, Nd3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Nd–O bond distances ranging from 2.44–2.93 Å. There are sixteen inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with two NdO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 11–43°. There are a spread of Ta–O bond distances ranging from 1.97–2.06 Å. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with two equivalent NdO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 9–39°. There are a spread of Ta–O bond distances ranging from 1.92–2.04 Å. In the third Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with two NdO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 10–44°. There are a spread of Ta–O bond distances ranging from 1.92–2.03 Å. In the fourth Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with two NdO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 10–39°. There are a spread of Ta–O bond distances ranging from 1.92–2.04 Å. In the fifth Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with two equivalent NdO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 9–43°. There are a spread of Ta–O bond distances ranging from 1.92–2.04 Å. In the sixth Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with two NdO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 11–44°. There are a spread of Ta–O bond distances ranging from 1.97–2.05 Å. In the seventh Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with two equivalent NdO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 9–43°. There are a spread of Ta–O bond distances ranging from 1.92–2.04 Å. In the eighth Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with two NdO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 10–39°. There are a spread of Ta–O bond distances ranging from 1.92–2.04 Å. In the ninth Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with two NdO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 11–44°. There are a spread of Ta–O bond distances ranging from 1.97–2.05 Å. In the tenth Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with two equivalent NdO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 9–38°. There are a spread of Ta–O bond distances ranging from 1.92–2.03 Å. In the eleventh Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with two NdO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 11–43°. There are a spread of Ta–O bond distances ranging from 1.96–2.05 Å. In the twelfth Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with two NdO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 10–44°. There are a spread of Ta–O bond distances ranging from 1.92–2.03 Å. In the thirteenth Ta5+ site, Ta5+ is bonded to six O2- atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–42°. There are a spread of Ta–O bond distances ranging from 1.90–2.11 Å. In the fourteenth Ta5+ site, Ta5+ is bonded to six O2- atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 6–39°. There is two shorter (1.95 Å) and four longer (2.02 Å) Ta–O bond length. In the fifteenth Ta5+ site, Ta5+ is bonded to six O2- atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 6–39°. There is two shorter (1.95 Å) and four longer (2.02 Å) Ta–O bond length. In the sixteenth Ta5+ site, Ta5+ is bonded to six O2- atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–42°. There are a spread of Ta–O bond distances ranging from 1.90–2.11 Å. There are forty-six inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a distorted T-shaped geometry to one Nd3+ and two Ta5+ atoms. In the third O2- site, O2- is bonded in a distorted linear geometry to one Nd3+ and two Ta5+ atoms. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Nd3+ and two Ta5+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Nd3+ and two Ta5+ atoms. In the sixth O2- site, O2- is bonded in a distorted T-shaped geometry to one Nd3+ and two Ta5+ atoms. In the seventh O2- site, O2- is bonded in a distorted T-shaped geometry to one Nd3+ and two Ta5+ atoms. In the eighth O2- site, O2- is bonded in a distorted linear geometry to one Nd3+ and two Ta5+ atoms. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to one Nd3+ and two Ta5+ atoms. In the tenth O2- site, O2- is bonded in a distorted T-shaped geometry to one Nd3+ and two Ta5+ atoms. In the eleventh O2- site, O2- is bonded in a distorted T-shaped geometry to one Nd3+ and two Ta5+ atoms. In the twelfth O2- site, O2- is bonded in a 3-coordinate geometry to one Nd3+ and two Ta5+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted linear geometry to one Nd3+ and two Ta5+ atoms. In the fourteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Ta5+ atoms. In the fifteenth O2- site, O2- is bonded in a 2-coordinate geometry to one Nd3+ and two Ta5+ atoms. In the sixteenth O2- site, O2- is bonded in a 2-coordinate geometry to one Nd3+ and two Ta5+ atoms. In the seventeenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Ta5+ atoms. In the eighteenth O2- site, O2- is bonded in a 2-coordinate geometry to one Nd3+ and two Ta5+ atoms. In the nineteenth O2- site, O2- is bonded in a 2-coordinate geometry to one Nd3+ and two Ta5+ atoms. In the twentieth O2- site, O2- is bonded in a distorted linear geometry to two equivalent Nd3+ and two Ta5+ atoms. In the twenty-first O2- site, O2- is bonded in a distorted linear geometry to two Nd3+ and two Ta5+ atoms. In the twenty-second O2- site, O2- is bonded in a 2-coordinate geometry to two Nd3+ and two Ta5+ atoms. In the twenty-third O2- site, O2- is bonded in a distorted linear geometry to two equivalent Nd3+ and two Ta5+ atoms. In the twenty-fourth O2- site, O2- is bonded in a 2-coordinate geometry to two Nd3+ and two Ta5+ atoms. In the twenty-fifth O2- site, O2- is bonded in a 2-coordinate geometry to two Nd3+ and two Ta5+ atoms. In the twenty-sixth O2- site, O2- is bonded in a 2-coordinate geometry to two Nd3+ and two Ta5+ atoms. In the twenty-seventh O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Nd3+ and two Ta5+ atoms. In the twenty-eighth O2- site, O2- is bonded in a 2-coordinate geometry to two Nd3+ and two Ta5+ atoms. In the twenty-ninth O2- site, O2- is bonded in a distorted linear geometry to two equivalent Nd3+ and two Ta5+ atoms. In the thirtieth O2- site, O2- is bonded in a 2-coordinate geometry to two Nd3+ and two Ta5+ atoms. In the thirty-first O2- site, O2- is bonded in a distorted linear geometry to two Nd3+ and two Ta5+ atoms. In the thirty-second O2- site, O2- is bonded in a 3-coordinate geometry to one Nd3+ and two Ta5+ atoms. In the thirty-third O2- site, O2- is bonded in a bent 150 degrees geometry to two Ta5+ atoms. In the thirty-fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Nd3+ and two Ta5+ atoms. In the thirty-fifth O2- site, O2- is bonded in a bent 150 degrees geometry to two Ta5+ atoms. In the thirty-sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Nd3+ and two Ta5+ atoms. In the thirty-seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Nd3+ and two Ta5+ atoms. In the thirty-eighth O2- site, O2- is bonded in a 3-coordinate geometry to one Nd3+ and two Ta5+ atoms. In the thirty-ninth O2- site, O2- is bonded in a 3-coordinate geometry to one Nd3+ and two Ta5+ atoms. In the fortieth O2- site, O2- is bonded in a bent 150 degrees geometry to two Ta5+ atoms. In the forty-first O2- site, O2- is bonded in a 3-coordinate geometry to one Nd3+ and two Ta5+ atoms. In the forty-second O2- site, O2- is bonded in a 3-coordinate geometry to one Nd3+ and two Ta5+ atoms. In the forty-third O2- site, O2- is bonded in a bent 150 degrees geometry to two Ta5+ atoms. In the forty-fourth O2- site, O2- is bonded in a distorted T-shaped geometry to one Nd3+ and two Ta5+ atoms. In the forty-fifth O2- site, O2- is bonded in a linear geometry to two equivalent Ta5+ atoms. In the forty-sixth O2- site, O2- is bonded in a distorted T-shaped geometry to one Nd3+ and two Ta5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta4SeS by Materials Project

Ta2SeTa2S crystallizes in the tetragonal P4mm space group. The structure is two-dimensional and consists of one Ta2S sheet oriented in the (0, 0, 1) direction and one Ta2Se sheet oriented in the (0, 0, 1) direction. In the Ta2S sheet, there are two inequivalent Ta sites. In the first Ta site, Ta is bonded in a 4-coordinate geometry to four equivalent S atoms. All Ta–S bond lengths are 2.56 Å. In the second Ta site, Ta is bonded in a distorted single-bond geometry to one S atom. The Ta–S bond length is 2.66 Å. S is bonded in a distorted pentagonal planar geometry to five Ta atoms. In the Ta2Se sheet, there are two inequivalent Ta sites. In the first Ta site, Ta is bonded in a 4-coordinate geometry to four equivalent Se atoms. All Ta–Se bond lengths are 2.69 Å. In the second Ta site, Ta is bonded in a 1-coordinate geometry to one Se atom. The Ta–Se bond length is 2.91 Å. Se is bonded in a 5-coordinate geometry to five Ta atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta5Ga2Sn by Materials Project

Ta5SnGa2 crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. there are two inequivalent Ta sites. In the first Ta site, Ta is bonded in a 7-coordinate geometry to one Ta, four equivalent Ga, and two equivalent Sn atoms. The Ta–Ta bond length is 2.77 Å. There are a spread of Ta–Ga bond distances ranging from 2.73–3.01 Å. Both Ta–Sn bond lengths are 2.89 Å. In the second Ta site, Ta is bonded in a 6-coordinate geometry to two equivalent Ta and four equivalent Ga atoms. Both Ta–Ta bond lengths are 2.67 Å. All Ta–Ga bond lengths are 2.79 Å. Ga is bonded in a 10-coordinate geometry to ten Ta atoms. Sn is bonded in a 10-coordinate geometry to eight equivalent Ta and two equivalent Sn atoms. Both Sn–Sn bond lengths are 2.67 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La2Ta3(SO4)2 by Materials Project

La2Ta3S2O8 crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. there are two inequivalent La3+ sites. In the first La3+ site, La3+ is bonded in a 9-coordinate geometry to two S2- and seven O2- atoms. There are one shorter (3.06 Å) and one longer (3.10 Å) La–S bond lengths. There are a spread of La–O bond distances ranging from 2.47–2.69 Å. In the second La3+ site, La3+ is bonded in a 9-coordinate geometry to two S2- and seven O2- atoms. There are one shorter (2.89 Å) and one longer (3.11 Å) La–S bond lengths. There are a spread of La–O bond distances ranging from 2.48–2.66 Å. There are two inequivalent Ta+4.67+ sites. In the first Ta+4.67+ site, Ta+4.67+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ta–O bond distances ranging from 1.86–2.33 Å. In the second Ta+4.67+ site, Ta+4.67+ is bonded in a 6-coordinate geometry to four S2- and two equivalent O2- atoms. There are two shorter (2.46 Å) and two longer (2.72 Å) Ta–S bond lengths. Both Ta–O bond lengths are 1.99 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 2-coordinate geometry to two La3+ and two equivalent Ta+4.67+ atoms. In the second S2- site, S2- is bonded in a 4-coordinate geometry to two La3+ and two equivalent Ta+4.67+ atoms. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one La3+ and two equivalent Ta+4.67+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two La3+ and one Ta+4.67+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two La3+ and two Ta+4.67+ atoms. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two La3+ and two equivalent Ta+4.67+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one La3+ and two equivalent Ta+4.67+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li2Ta3N5 by Materials Project

Li2Ta3N5 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to six N3- atoms to form LiN6 octahedra that share corners with three LiN6 octahedra, corners with three TaN6 octahedra, edges with four LiN6 octahedra, and edges with eight TaN6 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. There are a spread of Li–N bond distances ranging from 2.11–2.37 Å. In the second Li1+ site, Li1+ is bonded to six N3- atoms to form LiN6 octahedra that share corners with three LiN6 octahedra, corners with three TaN6 octahedra, edges with two LiN6 octahedra, and edges with ten TaN6 octahedra. The corner-sharing octahedra tilt angles range from 1–9°. There are a spread of Li–N bond distances ranging from 2.11–2.25 Å. There are three inequivalent Ta+4.33+ sites. In the first Ta+4.33+ site, Ta+4.33+ is bonded to six N3- atoms to form TaN6 octahedra that share corners with two LiN6 octahedra, corners with four TaN6 octahedra, edges with five TaN6 octahedra, and edges with seven LiN6 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. There are a spread of Ta–N bond distances ranging from 2.07–2.20 Å. In the second Ta+4.33+ site, Ta+4.33+ is bonded to six N3- atoms to form TaN6 octahedra that share corners with two LiN6 octahedra, corners with four TaN6 octahedra, edges with six LiN6 octahedra, and edges with six TaN6 octahedra. The corner-sharing octahedra tilt angles range from 1–7°. There are a spread of Ta–N bond distances ranging from 2.07–2.25 Å. In the third Ta+4.33+ site, Ta+4.33+ is bonded to six N3- atoms to form TaN6 octahedra that share corners with two LiN6 octahedra, corners with four TaN6 octahedra, edges with five equivalent LiN6 octahedra, and edges with seven TaN6 octahedra. The corner-sharing octahedra tilt angles range from 1–6°. There are a spread of Ta–N bond distances ranging from 2.12–2.22 Å. There are five inequivalent N3- sites. In the first N3- site, N3- is bonded to three Li1+ and three Ta+4.33+ atoms to form a mixture of edge and corner-sharing NLi3Ta3 octahedra. The corner-sharing octahedra tilt angles range from 1–9°. In the second N3- site, N3- is bonded to three equivalent Li1+ and three Ta+4.33+ atoms to form a mixture of edge and corner-sharing NLi3Ta3 octahedra. The corner-sharing octahedra tilt angles range from 1–5°. In the third N3- site, N3- is bonded to two equivalent Li1+ and four Ta+4.33+ atoms to form a mixture of edge and corner-sharing NLi2Ta4 octahedra. The corner-sharing octahedra tilt angles range from 1–4°. In the fourth N3- site, N3- is bonded to two equivalent Li1+ and four Ta+4.33+ atoms to form NLi2Ta4 octahedra that share corners with six NLi3Ta3 octahedra and edges with twelve NLi2Ta4 octahedra. The corner-sharing octahedra tilt angles range from 1–6°. In the fifth N3- site, N3- is bonded to two Li1+ and four Ta+4.33+ atoms to form NLi2Ta4 octahedra that share corners with six NLi3Ta3 octahedra and edges with twelve NLi2Ta4 octahedra. The corner-sharing octahedra tilt angles range from 2–7°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta2CN by Materials Project

Ta2CN is Caswellsilverite-like structured and crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. there are three inequivalent Ta+3.50+ sites. In the first Ta+3.50+ site, Ta+3.50+ is bonded to three equivalent C4- and three equivalent N3- atoms to form a mixture of edge and corner-sharing TaC3N3 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are one shorter (2.16 Å) and two longer (2.23 Å) Ta–C bond lengths. There are two shorter (2.23 Å) and one longer (2.33 Å) Ta–N bond lengths. In the second Ta+3.50+ site, Ta+3.50+ is bonded to three equivalent C4- and three equivalent N3- atoms to form a mixture of edge and corner-sharing TaC3N3 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are one shorter (2.16 Å) and two longer (2.23 Å) Ta–C bond lengths. There are two shorter (2.23 Å) and one longer (2.33 Å) Ta–N bond lengths. In the third Ta+3.50+ site, Ta+3.50+ is bonded to three equivalent C4- and three equivalent N3- atoms to form a mixture of edge and corner-sharing TaC3N3 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are one shorter (2.16 Å) and two longer (2.23 Å) Ta–C bond lengths. There are two shorter (2.23 Å) and one longer (2.33 Å) Ta–N bond lengths. C4- is bonded to six Ta+3.50+ atoms to form CTa6 octahedra that share corners with two equivalent NTa6 octahedra, corners with four equivalent CTa6 octahedra, edges with four equivalent CTa6 octahedra, and edges with eight equivalent NTa6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. N3- is bonded to six Ta+3.50+ atoms to form NTa6 octahedra that share corners with two equivalent CTa6 octahedra, corners with four equivalent NTa6 octahedra, edges with four equivalent NTa6 octahedra, and edges with eight equivalent CTa6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaPd3 by Materials Project

Pd3Ta is Uranium Silicide-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are three inequivalent Ta sites. In the first Ta site, Ta is bonded to twelve Pd atoms to form TaPd12 cuboctahedra that share corners with twelve TaPd12 cuboctahedra, edges with eighteen PdTa4Pd8 cuboctahedra, faces with six equivalent TaPd12 cuboctahedra, and faces with twelve PdTa4Pd8 cuboctahedra. There are six shorter (2.78 Å) and six longer (2.82 Å) Ta–Pd bond lengths. In the second Ta site, Ta is bonded to twelve Pd atoms to form TaPd12 cuboctahedra that share corners with six equivalent PdTa4Pd8 cuboctahedra, corners with nine TaPd12 cuboctahedra, edges with nine PdTa4Pd8 cuboctahedra, faces with three equivalent PdTa4Pd8 cuboctahedra, and faces with seven TaPd12 cuboctahedra. There are a spread of Ta–Pd bond distances ranging from 2.76–2.98 Å. In the third Ta site, Ta is bonded to twelve Pd atoms to form TaPd12 cuboctahedra that share corners with six equivalent TaPd12 cuboctahedra, corners with six equivalent PdTa4Pd8 cuboctahedra, edges with twelve PdTa4Pd8 cuboctahedra, faces with eight TaPd12 cuboctahedra, and faces with nine PdTa4Pd8 cuboctahedra. There are six shorter (2.78 Å) and six longer (2.81 Å) Ta–Pd bond lengths. There are four inequivalent Pd sites. In the first Pd site, Pd is bonded to four Ta and eight Pd atoms to form distorted PdTa4Pd8 cuboctahedra that share corners with six equivalent PdTa4Pd8 cuboctahedra, edges with eight TaPd12 cuboctahedra, edges with twelve PdTa4Pd8 cuboctahedra, faces with four TaPd12 cuboctahedra, and faces with fourteen PdTa4Pd8 cuboctahedra. Both Pd–Ta bond lengths are 2.81 Å. There are a spread of Pd–Pd bond distances ranging from 2.77–2.82 Å. In the second Pd site, Pd is bonded to four Ta and eight Pd atoms to form distorted PdTa4Pd8 cuboctahedra that share corners with four TaPd12 cuboctahedra, corners with ten equivalent PdTa4Pd8 cuboctahedra, edges with six TaPd12 cuboctahedra, edges with eight PdTa4Pd8 cuboctahedra, faces with four TaPd12 cuboctahedra, and faces with ten PdTa4Pd8 cuboctahedra. There are a spread of Pd–Pd bond distances ranging from 2.78–2.82 Å. In the third Pd site, Pd is bonded in a distorted see-saw-like geometry to four Ta and two equivalent Pd atoms. In the fourth Pd site, Pd is bonded to four Ta and eight Pd atoms to form distorted PdTa4Pd8 cuboctahedra that share corners with six equivalent PdTa4Pd8 cuboctahedra, edges with eight TaPd12 cuboctahedra, edges with twelve PdTa4Pd8 cuboctahedra, faces with four TaPd12 cuboctahedra, and faces with fourteen PdTa4Pd8 cuboctahedra. There are one shorter (2.77 Å) and one longer (2.80 Å) Pd–Pd bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr2Ta3(SeO4)2 by Materials Project

Pr2Ta3Se2O8 crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. there are two inequivalent Pr3+ sites. In the first Pr3+ site, Pr3+ is bonded in a 9-coordinate geometry to two Se2- and seven O2- atoms. There are one shorter (3.09 Å) and one longer (3.10 Å) Pr–Se bond lengths. There are a spread of Pr–O bond distances ranging from 2.53–2.61 Å. In the second Pr3+ site, Pr3+ is bonded in a 9-coordinate geometry to two Se2- and seven O2- atoms. There are one shorter (2.96 Å) and one longer (3.07 Å) Pr–Se bond lengths. There are a spread of Pr–O bond distances ranging from 2.50–2.64 Å. There are two inequivalent Ta+4.67+ sites. In the first Ta+4.67+ site, Ta+4.67+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ta–O bond distances ranging from 1.85–2.38 Å. In the second Ta+4.67+ site, Ta+4.67+ is bonded in a 6-coordinate geometry to four Se2- and two equivalent O2- atoms. There are two shorter (2.57 Å) and two longer (2.76 Å) Ta–Se bond lengths. Both Ta–O bond lengths are 2.00 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 2-coordinate geometry to two Pr3+ and two equivalent Ta+4.67+ atoms. In the second Se2- site, Se2- is bonded in a 4-coordinate geometry to two Pr3+ and two equivalent Ta+4.67+ atoms. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Pr3+ and two equivalent Ta+4.67+ atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two Pr3+ and one Ta+4.67+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two Pr3+ and two Ta+4.67+ atoms. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two Pr3+ and two equivalent Ta+4.67+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Pr3+ and two equivalent Ta+4.67+ atoms.

36 MATERIALS SCIENCE↗