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DOE OSTI2020

Materials Data on Ba3Ta5O15 by Materials Project

Ba3Ta5O15 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share faces with two equivalent BaO12 cuboctahedra and faces with eight equivalent TaO6 octahedra. There are eight shorter (2.83 Å) and four longer (2.84 Å) Ba–O bond lengths. In the second Ba2+ site, Ba2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are two shorter (2.87 Å) and four longer (2.89 Å) Ba–O bond lengths. There are two inequivalent Ta+4.80+ sites. In the first Ta+4.80+ site, Ta+4.80+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with two equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 2–38°. There are a spread of Ta–O bond distances ranging from 1.98–2.07 Å. In the second Ta+4.80+ site, Ta+4.80+ is bonded to six O2- atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–35°. There are four shorter (2.00 Å) and two longer (2.01 Å) Ta–O bond lengths. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to two equivalent Ta+4.80+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+ and two equivalent Ta+4.80+ atoms. In the third O2- site, O2- is bonded in a distorted linear geometry to one Ba2+ and two equivalent Ta+4.80+ atoms. In the fourth O2- site, O2- is bonded in a distorted linear geometry to two equivalent Ba2+ and two equivalent Ta+4.80+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ba2+ and two Ta+4.80+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba2Ta15O32 by Materials Project

Ba2Ta15O32 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. Ba2+ is bonded to twelve O2- atoms to form distorted BaO12 cuboctahedra that share corners with six TaO6 octahedra, edges with three equivalent BaO12 cuboctahedra, edges with three equivalent TaO6 octahedra, edges with three equivalent TaO5 square pyramids, and faces with three equivalent TaO6 octahedra. The corner-sharing octahedra tilt angles range from 44–55°. There are a spread of Ba–O bond distances ranging from 2.94–3.19 Å. There are four inequivalent Ta4+ sites. In the first Ta4+ site, Ta4+ is bonded to five O2- atoms to form TaO5 square pyramids that share corners with four TaO6 octahedra, corners with four equivalent TaO5 square pyramids, an edgeedge with one BaO12 cuboctahedra, and an edgeedge with one TaO6 octahedra. The corner-sharing octahedra tilt angles range from 7–54°. There are a spread of Ta–O bond distances ranging from 2.06–2.22 Å. In the second Ta4+ site, Ta4+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three equivalent TaO6 octahedra, corners with three equivalent TaO5 square pyramids, and edges with three equivalent TaO5 square pyramids. The corner-sharing octahedral tilt angles are 42°. There are three shorter (1.95 Å) and three longer (2.08 Å) Ta–O bond lengths. In the third Ta4+ site, Ta4+ is bonded to six O2- atoms to form TaO6 octahedra that share a cornercorner with one BaO12 cuboctahedra, corners with two TaO6 octahedra, corners with three equivalent TaO5 square pyramids, an edgeedge with one BaO12 cuboctahedra, edges with two equivalent TaO6 octahedra, and a faceface with one BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 38–42°. There are a spread of Ta–O bond distances ranging from 1.91–2.11 Å. In the fourth Ta4+ site, Ta4+ is bonded to six equivalent O2- atoms to form TaO6 octahedra that share corners with six equivalent BaO12 cuboctahedra and corners with six equivalent TaO6 octahedra. The corner-sharing octahedral tilt angles are 38°. All Ta–O bond lengths are 2.00 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+ and three Ta4+ atoms. In the second O2- site, O2- is bonded in a T-shaped geometry to three Ta4+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three equivalent Ta4+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+ and two Ta4+ atoms. In the fifth O2- site, O2- is bonded in a distorted water-like geometry to two equivalent Ba2+ and two equivalent Ta4+ atoms. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to three Ta4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba5Ta4O15 by Materials Project

Ba5Ta4O15 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. there are three inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine equivalent BaO12 cuboctahedra, faces with three equivalent BaO12 cuboctahedra, and faces with seven TaO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.71–3.05 Å. In the second Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with six equivalent BaO12 cuboctahedra, faces with six equivalent BaO12 cuboctahedra, and faces with eight TaO6 octahedra. There are six shorter (2.86 Å) and six longer (2.93 Å) Ba–O bond lengths. In the third Ba2+ site, Ba2+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are a spread of Ba–O bond distances ranging from 2.79–3.33 Å. There are two 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 seven BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–8°. There are three shorter (1.97 Å) and three longer (2.10 Å) Ta–O bond lengths. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form distorted TaO6 octahedra that share corners with three equivalent TaO6 octahedra and faces with four BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 8°. There are three shorter (1.87 Å) and three longer (2.26 Å) Ta–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to four Ba2+ and one Ta5+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+ and two Ta5+ atoms. In the third O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two equivalent Ta5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaTa2O6 by Materials Project

BaTa2O6 crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. there are four inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.84–3.21 Å. In the second Ba2+ site, Ba2+ is bonded in a 6-coordinate geometry to six equivalent O2- atoms. All Ba–O bond lengths are 2.73 Å. In the third Ba2+ site, Ba2+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Ba–O bond lengths are 2.66 Å. In the fourth Ba2+ site, Ba2+ is bonded in a hexagonal planar geometry to six equivalent O2- atoms. All Ba–O bond lengths are 2.71 Å. There are three inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 6–35°. There are a spread of Ta–O bond distances ranging from 1.93–2.05 Å. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 3–34°. There are four shorter (1.99 Å) and two longer (2.02 Å) Ta–O bond lengths. In the third Ta5+ site, Ta5+ is bonded to six O2- atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 7–34°. There are a spread of Ta–O bond distances ranging from 1.97–2.03 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to one Ba2+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a distorted linear geometry to one Ba2+ and two equivalent Ta5+ atoms. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ba2+ and two Ta5+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ba2+ and two equivalent Ta5+ atoms. In the fifth O2- site, O2- is bonded in a linear geometry to two Ta5+ atoms. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+ and two equivalent Ta5+ atoms. In the seventh O2- site, O2- is bonded in a linear geometry to two equivalent Ta5+ atoms. In the eighth O2- site, O2- is bonded to two equivalent Ba2+ and two equivalent Ta5+ atoms to form a mixture of distorted edge and corner-sharing OBa2Ta2 tetrahedra. In the ninth O2- site, O2- is bonded to two equivalent Ba2+ and two equivalent Ta5+ atoms to form a mixture of distorted edge and corner-sharing OBa2Ta2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaTa2O6 by Materials Project

BaTa2O6 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are six inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ba–O bond distances ranging from 2.66–3.35 Å. In the second Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ba–O bond distances ranging from 2.70–3.16 Å. In the third Ba2+ site, Ba2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ba–O bond distances ranging from 2.55–3.27 Å. In the fourth Ba2+ site, Ba2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ba–O bond distances ranging from 2.57–3.05 Å. In the fifth Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ba–O bond distances ranging from 2.67–3.23 Å. In the sixth Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.69–3.11 Å. There are twelve inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Ta–O bond distances ranging from 1.83–2.26 Å. In the second Ta5+ site, Ta5+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Ta–O bond distances ranging from 1.77–2.06 Å. In the third Ta5+ site, Ta5+ is bonded to four O2- atoms to form corner-sharing TaO4 tetrahedra. There are a spread of Ta–O bond distances ranging from 1.79–1.92 Å. In the fourth Ta5+ site, Ta5+ is bonded to four O2- atoms to form corner-sharing TaO4 tetrahedra. There are a spread of Ta–O bond distances ranging from 1.82–1.96 Å. In the fifth Ta5+ site, Ta5+ is bonded to four O2- atoms to form corner-sharing TaO4 tetrahedra. There are a spread of Ta–O bond distances ranging from 1.81–1.97 Å. In the sixth Ta5+ site, Ta5+ is bonded to five O2- atoms to form TaO5 trigonal bipyramids that share a cornercorner with one TaO4 tetrahedra and a cornercorner with one TaO5 trigonal bipyramid. There are a spread of Ta–O bond distances ranging from 1.84–2.15 Å. In the seventh Ta5+ site, Ta5+ is bonded to five O2- atoms to form distorted TaO5 trigonal bipyramids that share a cornercorner with one TaO4 tetrahedra and corners with two TaO5 trigonal bipyramids. There are a spread of Ta–O bond distances ranging from 1.82–2.27 Å. In the eighth Ta5+ site, Ta5+ is bonded to five O2- atoms to form TaO5 trigonal bipyramids that share a cornercorner with one TaO4 tetrahedra and a cornercorner with one TaO5 trigonal bipyramid. There are a spread of Ta–O bond distances ranging from 1.82–2.22 Å. In the ninth Ta5+ site, Ta5+ is bonded to five O2- atoms to form distorted TaO5 trigonal bipyramids that share a cornercorner with one TaO4 tetrahedra and a cornercorner with one TaO5 trigonal bipyramid. There are a spread of Ta–O bond distances ranging from 1.80–2.29 Å. In the tenth Ta5+ site, Ta5+ is bonded to four O2- atoms to form TaO4 tetrahedra that share corners with two TaO4 tetrahedra and a cornercorner with one TaO5 trigonal bipyramid. There are a spread of Ta–O bond distances ranging from 1.81–1.97 Å. In the eleventh Ta5+ site, Ta5+ is bonded to four O2- atoms to form TaO4 tetrahedra that share a cornercorner with one TaO4 tetrahedra and a cornercorner with one TaO5 trigonal bipyramid. There are a spread of Ta–O bond distances ranging from 1.82–1.96 Å. In the twelfth Ta5+ site, Ta5+ is bonded to five O2- atoms to form distorted TaO5 trigonal bipyramids that share corners with two TaO4 tetrahedra and a cornercorner with one TaO5 trigonal bipyramid. There are a spread of Ta–O bond distances ranging from 1.80–2.16 Å. There are thirty-six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two Ba2+ and two Ta5+ atoms. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two Ba2+ and one Ta5+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to two Ba2+ and one Ta5+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to one Ba2+ and one Ta5+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+ and two Ta5+ atoms. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to two Ba2+ and one Ta5+ atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to two Ba2+ and one Ta5+ atom. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to two Ba2+ and one Ta5+ atom. In the ninth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two Ba2+ and one Ta5+ atom. In the tenth O2- site, O2- is bonded in a bent 120 degrees geometry to two Ta5+ atoms. In the eleventh O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+ and two Ta5+ atoms. In the twelfth O2- site, O2- is bonded in a bent 150 degrees geometry to two Ta5+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ba2+ and two Ta5+ atoms. In the fourteenth O2- site, O2- is bonded in a 1-coordinate geometry to one Ba2+ and one Ta5+ atom. In the fifteenth O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+ and two Ta5+ atoms. In the sixteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+ and one Ta5+ atom. In the seventeenth O2- site, O2- is bonded in a single-bond geometry to one Ta5+ atom. In the eighteenth O2- site, O2- is bonded in a bent 120 degrees geometry to one Ba2+ and two Ta5+ atoms. In the nineteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Ta5+ atoms. In the twentieth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ba2+ and two Ta5+ atoms. In the twenty-first O2- site, O2- is bonded in a bent 150 degrees geometry to two Ta5+ atoms. In the twenty-second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ba2+ and one Ta5+ atom. In the twenty-third O2- site, O2- is bonded in a 1-coordinate geometry to two Ba2+ and one Ta5+ atom. In the twenty-fourth O2- site, O2- is bonded in a distorted single-bond geometry to two Ba2+ and one Ta5+ atom. In the twenty-fifth O2- site, O2- is bonded in a distorted single-bond geometry to two Ba2+ and one Ta5+ atom. In the twenty-sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Ta5+ atoms. In the twenty-seventh O2- site, O2- is bonded in a 1-coordinate geometry to one Ba2+ and two Ta5+ atoms. In the twenty-eighth O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+ and two Ta5+ atoms. In the twenty-ninth O2- site, O2- is bonded in a 1-coordinate geometry to one Ba2+ and two Ta5+ atoms. In the thirtieth O2- site, O2- is bonded in a 1-coordinate geometry to two Ba2+ and one Ta5+ atom. In the thirty-first O2- site, O2- is bonded in a distorted single-bond geometry to one Ba2+ and one Ta5+ atom. In the thirty-second O2- site, O2- is bonded in a distorted single-bond geometry to two Ba2+ and one Ta5+ atom. In the thirty-third O2- site, O2- is bonded in a distorted single-bond geometry to two Ba2+ and one Ta5+ atom. In the thirty-fourth O2- site, O2- is bonded in a bent 150 degrees geometry to 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 2-coordinate geometry to one Ba2+ and two Ta5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaTaO3 by Materials Project

BaTaO3 is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ba2+ is bonded to twelve equivalent O2- atoms to form BaO12 cuboctahedra that share corners with twelve equivalent BaO12 cuboctahedra, faces with six equivalent BaO12 cuboctahedra, and faces with eight equivalent TaO6 octahedra. All Ba–O bond lengths are 2.92 Å. Ta4+ is bonded to six equivalent O2- atoms to form TaO6 octahedra that share corners with six equivalent TaO6 octahedra and faces with eight equivalent BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Ta–O bond lengths are 2.07 Å. O2- is bonded in a distorted linear geometry to four equivalent Ba2+ and two equivalent Ta4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba4Ta2O9 by Materials Project

Ba4Ta2O9 is Orthorhombic Perovskite-like structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are five inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to six O2- atoms to form BaO6 octahedra that share corners with six TaO6 octahedra. The corner-sharing octahedra tilt angles range from 19–28°. There are a spread of Ba–O bond distances ranging from 2.57–2.60 Å. In the second Ba2+ site, Ba2+ is bonded to six O2- atoms to form BaO6 octahedra that share corners with six TaO6 octahedra. The corner-sharing octahedra tilt angles range from 23–28°. There are two shorter (2.58 Å) and four longer (2.59 Å) Ba–O bond lengths. In the third Ba2+ site, Ba2+ is bonded in a 11-coordinate geometry to eleven O2- atoms. There are a spread of Ba–O bond distances ranging from 2.69–3.34 Å. In the fourth Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.70–3.08 Å. In the fifth Ba2+ site, Ba2+ is bonded in a 3-coordinate geometry to five O2- atoms. There are a spread of Ba–O bond distances ranging from 2.65–2.97 Å. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three BaO6 octahedra and corners with three TaO6 octahedra. The corner-sharing octahedra tilt angles range from 13–28°. There are a spread of Ta–O bond distances ranging from 1.92–2.22 Å. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three BaO6 octahedra and corners with three TaO6 octahedra. The corner-sharing octahedra tilt angles range from 16–28°. There are a spread of Ta–O bond distances ranging from 1.93–2.23 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to three Ba2+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three Ba2+ and two Ta5+ atoms. In the third O2- site, O2- is bonded in a 1-coordinate geometry to three Ba2+ and one Ta5+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to four Ba2+ and one Ta5+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to four Ba2+ and one Ta5+ atom. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to three Ba2+ and one Ta5+ atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to three Ba2+ and one Ta5+ atom. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to three Ba2+ and one Ta5+ atom. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+ and two equivalent Ta5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaTa6O16 by Materials Project

BaTa6O16 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.71–2.91 Å. There are four inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to seven O2- atoms to form TaO7 pentagonal bipyramids that share corners with two equivalent TaO7 pentagonal bipyramids and edges with five TaO6 octahedra. There are a spread of Ta–O bond distances ranging from 1.96–2.15 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 an edgeedge with one TaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 2–44°. There are a spread of Ta–O bond distances ranging from 1.96–2.08 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 an edgeedge with one TaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 7–44°. There are a spread of Ta–O bond distances ranging from 1.96–2.01 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 an edgeedge with one TaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 18–38°. There are a spread of Ta–O bond distances ranging from 1.89–2.13 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+ and two Ta5+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to three Ta5+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to three Ta5+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+ and two equivalent Ta5+ atoms. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to two Ta5+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Ta5+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+ and two equivalent Ta5+ atoms. In the eighth O2- site, O2- is bonded in a linear geometry to two equivalent Ta5+ atoms. In the ninth O2- site, O2- is bonded in a linear geometry to two equivalent Ta5+ atoms. In the tenth O2- site, O2- is bonded in a distorted linear geometry to one Ba2+ and two equivalent Ta5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba4Ta2O9 by Materials Project

Ba4Ta2O9 is Ilmenite-like structured and crystallizes in the trigonal P-3c1 space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 6-coordinate geometry to six equivalent O2- atoms. There are three shorter (2.66 Å) and three longer (2.97 Å) Ba–O bond lengths. In the second Ba2+ site, Ba2+ is bonded to six O2- atoms to form distorted BaO6 pentagonal pyramids that share corners with three equivalent TaO6 octahedra, corners with three equivalent BaO6 pentagonal pyramids, and edges with three equivalent TaO6 octahedra. The corner-sharing octahedral tilt angles are 50°. There are three shorter (2.56 Å) and three longer (2.74 Å) Ba–O bond lengths. Ta5+ is bonded to six O2- atoms to form distorted TaO6 octahedra that share corners with three equivalent BaO6 pentagonal pyramids, edges with three equivalent BaO6 pentagonal pyramids, and a faceface with one TaO6 octahedra. There are three shorter (1.95 Å) and three longer (2.14 Å) Ta–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to three Ba2+ and one Ta5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaTa4O11 by Materials Project

BaTa4O11 crystallizes in the hexagonal P6_322 space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are six shorter (2.64 Å) and two longer (2.73 Å) Ba–O bond lengths. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded in a 7-coordinate geometry to six O2- atoms. There are a spread of Ta–O bond distances ranging from 1.98–2.10 Å. In the second Ta5+ site, Ta5+ is bonded in an octahedral geometry to six equivalent O2- atoms. All Ta–O bond lengths are 2.00 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+ and two Ta5+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three equivalent Ta5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba2Ta2O7 by Materials Project

Ba2Ta2O7 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 6-coordinate geometry to six equivalent O2- atoms. There are four shorter (2.60 Å) and two longer (2.78 Å) Ba–O bond lengths. In the second Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with six equivalent BaO12 cuboctahedra, faces with four equivalent BaO12 cuboctahedra, and faces with eight TaO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.74–2.97 Å. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with four TaO6 octahedra and faces with two equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 8–13°. There are a spread of Ta–O bond distances ranging from 1.86–2.23 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 six equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–10°. There are a spread of Ta–O bond distances ranging from 1.93–2.15 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to four equivalent Ba2+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+ and two Ta5+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to three equivalent Ba2+ and one Ta5+ atom. In the fourth O2- site, O2- is bonded in a distorted linear geometry to three equivalent Ba2+ and two equivalent Ta5+ atoms. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+ and two equivalent Ta5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba8Ta7O24 by Materials Project

Ba8Ta7O24 crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. there are eight inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, faces with six BaO12 cuboctahedra, and faces with eight TaO6 octahedra. There are three shorter (2.88 Å) and nine longer (2.96 Å) Ba–O bond lengths. In the second Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are three shorter (2.78 Å) and six longer (3.02 Å) Ba–O bond lengths. In the third Ba2+ site, Ba2+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are a spread of Ba–O bond distances ranging from 2.63–3.27 Å. In the fourth Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with twelve BaO12 cuboctahedra, faces with six BaO12 cuboctahedra, and faces with eight TaO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.82–2.98 Å. In the fifth Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form distorted BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, faces with six BaO12 cuboctahedra, and faces with seven TaO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.69–3.11 Å. In the sixth Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with six equivalent BaO12 cuboctahedra, corners with three equivalent TaO6 octahedra, faces with four BaO12 cuboctahedra, and faces with seven TaO6 octahedra. The corner-sharing octahedral tilt angles are 14°. There are a spread of Ba–O bond distances ranging from 2.88–2.96 Å. In the seventh Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form distorted BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, faces with three equivalent BaO12 cuboctahedra, and faces with five TaO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.89–3.15 Å. In the eighth Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, corners with three equivalent TaO6 octahedra, faces with seven BaO12 cuboctahedra, and faces with seven TaO6 octahedra. The corner-sharing octahedral tilt angles are 13°. There are a spread of Ba–O bond distances ranging from 2.84–3.06 Å. There are seven inequivalent Ta+4.57+ sites. In the first Ta+4.57+ site, Ta+4.57+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with four BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 6–8°. There are three shorter (1.96 Å) and three longer (2.10 Å) Ta–O bond lengths. In the second Ta+4.57+ site, Ta+4.57+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent TaO6 octahedra, faces with six BaO12 cuboctahedra, and a faceface with one TaO6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are three shorter (2.05 Å) and three longer (2.09 Å) Ta–O bond lengths. In the third Ta+4.57+ site, Ta+4.57+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent TaO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one TaO6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are three shorter (2.07 Å) and three longer (2.10 Å) Ta–O bond lengths. In the fourth Ta+4.57+ site, Ta+4.57+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three equivalent TaO6 octahedra and faces with seven BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 7°. There are three shorter (1.88 Å) and three longer (2.26 Å) Ta–O bond lengths. In the fifth Ta+4.57+ site, Ta+4.57+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with eight BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 2°. There are three shorter (2.05 Å) and three longer (2.06 Å) Ta–O bond lengths. In the sixth Ta+4.57+ site, Ta+4.57+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with eight BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 2–7°. There are three shorter (2.00 Å) and three longer (2.10 Å) Ta–O bond lengths. In the seventh Ta+4.57+ site, Ta+4.57+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three equivalent TaO6 octahedra and faces with two BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 8°. There are three shorter (1.88 Å) and three longer (2.22 Å) Ta–O bond lengths. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to four Ba2+ and one Ta+4.57+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to three Ba2+ and two Ta+4.57+ atoms. In the third O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two Ta+4.57+ atoms. In the fourth O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two Ta+4.57+ atoms. In the fifth O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two Ta+4.57+ atoms. In the sixth O2- site, O2- is bonded in a 6-coordinate geometry to four Ba2+ and two Ta+4.57+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+ and two Ta+4.57+ atoms. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to four Ba2+ and one Ta+4.57+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba4Ta2O9 by Materials Project

Ba4Ta2O9 crystallizes in the hexagonal P6_3/m space group. The structure is three-dimensional. there are three inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are a spread of Ba–O bond distances ranging from 2.84–3.31 Å. In the second Ba2+ site, Ba2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are three shorter (2.73 Å) and three longer (2.79 Å) Ba–O bond lengths. In the third Ba2+ site, Ba2+ is bonded to six equivalent O2- atoms to form distorted BaO6 octahedra that share corners with six equivalent TaO6 octahedra. The corner-sharing octahedral tilt angles are 26°. All Ba–O bond lengths are 2.67 Å. Ta5+ is bonded to six O2- atoms to form distorted TaO6 octahedra that share corners with three equivalent BaO6 octahedra and a faceface with one TaO6 octahedra. The corner-sharing octahedral tilt angles are 26°. There are three shorter (1.91 Å) and three longer (2.17 Å) Ta–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to four Ba2+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to three Ba2+ and one Ta5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba2Ta15O32 by Materials Project

Ba2Ta15O32 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form distorted BaO12 cuboctahedra that share corners with six TaO6 octahedra, edges with three equivalent BaO12 cuboctahedra, edges with three TaO6 octahedra, edges with three TaO5 square pyramids, and faces with three TaO6 octahedra. The corner-sharing octahedra tilt angles range from 43–55°. There are a spread of Ba–O bond distances ranging from 2.89–3.23 Å. In the second Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form distorted BaO12 cuboctahedra that share corners with six TaO6 octahedra, edges with three equivalent BaO12 cuboctahedra, edges with three TaO6 octahedra, edges with three TaO5 square pyramids, and faces with three TaO6 octahedra. The corner-sharing octahedra tilt angles range from 43–55°. There are a spread of Ba–O bond distances ranging from 2.89–3.23 Å. There are fifteen inequivalent Ta4+ sites. In the first Ta4+ site, Ta4+ is bonded to six O2- atoms to form TaO6 octahedra that share a cornercorner with one BaO12 cuboctahedra, corners with two TaO6 octahedra, corners with three TaO5 square pyramids, an edgeedge with one BaO12 cuboctahedra, edges with two TaO6 octahedra, and a faceface with one BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 39–42°. There are a spread of Ta–O bond distances ranging from 1.92–2.10 Å. In the second Ta4+ site, Ta4+ is bonded to six O2- atoms to form TaO6 octahedra that share a cornercorner with one BaO12 cuboctahedra, corners with two TaO6 octahedra, corners with three TaO5 square pyramids, an edgeedge with one BaO12 cuboctahedra, edges with two TaO6 octahedra, and a faceface with one BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 39–42°. There are a spread of Ta–O bond distances ranging from 1.91–2.12 Å. In the third Ta4+ site, Ta4+ is bonded to six O2- atoms to form TaO6 octahedra that share a cornercorner with one BaO12 cuboctahedra, corners with two TaO6 octahedra, corners with three TaO5 square pyramids, an edgeedge with one BaO12 cuboctahedra, edges with two TaO6 octahedra, and a faceface with one BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 39–42°. There are a spread of Ta–O bond distances ranging from 1.91–2.12 Å. In the fourth Ta4+ site, Ta4+ is bonded to six O2- atoms to form TaO6 octahedra that share a cornercorner with one BaO12 cuboctahedra, corners with two TaO6 octahedra, corners with three TaO5 square pyramids, an edgeedge with one BaO12 cuboctahedra, edges with two TaO6 octahedra, and a faceface with one BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 39–42°. There are a spread of Ta–O bond distances ranging from 1.92–2.11 Å. In the fifth Ta4+ site, Ta4+ is bonded to six O2- atoms to form TaO6 octahedra that share a cornercorner with one BaO12 cuboctahedra, corners with two TaO6 octahedra, corners with three TaO5 square pyramids, an edgeedge with one BaO12 cuboctahedra, edges with two TaO6 octahedra, and a faceface with one BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 40–42°. There are a spread of Ta–O bond distances ranging from 1.92–2.11 Å. In the sixth Ta4+ site, Ta4+ is bonded to six O2- atoms to form TaO6 octahedra that share a cornercorner with one BaO12 cuboctahedra, corners with two TaO6 octahedra, corners with three TaO5 square pyramids, an edgeedge with one BaO12 cuboctahedra, edges with two TaO6 octahedra, and a faceface with one BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 38–43°. There are a spread of Ta–O bond distances ranging from 1.91–2.12 Å. In the seventh Ta4+ site, Ta4+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six BaO12 cuboctahedra and corners with six TaO6 octahedra. The corner-sharing octahedra tilt angles range from 38–40°. There are three shorter (2.00 Å) and three longer (2.01 Å) Ta–O bond lengths. In the eighth Ta4+ site, Ta4+ is bonded to five O2- atoms to form TaO5 square pyramids that share corners with four TaO6 octahedra, corners with four TaO5 square pyramids, an edgeedge with one BaO12 cuboctahedra, and an edgeedge with one TaO6 octahedra. The corner-sharing octahedra tilt angles range from 6–53°. There are a spread of Ta–O bond distances ranging from 2.06–2.22 Å. In the ninth Ta4+ site, Ta4+ is bonded to five O2- atoms to form TaO5 square pyramids that share corners with four TaO6 octahedra, corners with four TaO5 square pyramids, an edgeedge with one BaO12 cuboctahedra, and an edgeedge with one TaO6 octahedra. The corner-sharing octahedra tilt angles range from 6–53°. There are a spread of Ta–O bond distances ranging from 2.06–2.22 Å. In the tenth Ta4+ site, Ta4+ is bonded to five O2- atoms to form TaO5 square pyramids that share corners with four TaO6 octahedra, corners with four TaO5 square pyramids, an edgeedge with one BaO12 cuboctahedra, and an edgeedge with one TaO6 octahedra. The corner-sharing octahedra tilt angles range from 6–54°. There are a spread of Ta–O bond distances ranging from 2.06–2.22 Å. In the eleventh Ta4+ site, Ta4+ is bonded to five O2- atoms to form TaO5 square pyramids that share corners with four TaO6 octahedra, corners with four TaO5 square pyramids, an edgeedge with one BaO12 cuboctahedra, and an edgeedge with one TaO6 octahedra. The corner-sharing octahedra tilt angles range from 6–54°. There are a spread of Ta–O bond distances ranging from 2.06–2.22 Å. In the twelfth Ta4+ site, Ta4+ is bonded to five O2- atoms to form TaO5 square pyramids that share corners with four TaO6 octahedra, corners with four TaO5 square pyramids, an edgeedge with one BaO12 cuboctahedra, and an edgeedge with one TaO6 octahedra. The corner-sharing octahedra tilt angles range from 6–53°. There are a spread of Ta–O bond distances ranging from 2.06–2.22 Å. In the thirteenth Ta4+ site, Ta4+ is bonded to five O2- atoms to form TaO5 square pyramids that share corners with four TaO6 octahedra, corners with four TaO5 square pyramids, an edgeedge with one BaO12 cuboctahedra, and an edgeedge with one TaO6 octahedra. The corner-sharing octahedra tilt angles range from 6–53°. There are a spread of Ta–O bond distances ranging from 2.06–2.23 Å. In the fourteenth Ta4+ site, Ta4+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three TaO6 octahedra, corners with three TaO5 square pyramids, and edges with three TaO5 square pyramids. The corner-sharing octahedral tilt angles are 42°. There are three shorter (1.95 Å) and three longer (2.09 Å) Ta–O bond lengths. In the fifteenth Ta4+ site, Ta4+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three TaO6 octahedra, corners with three TaO5 square pyramids, and edges with three TaO5 square pyramids. The corner-sharing octahedra tilt angles range from 42–43°. There are three shorter (1.95 Å) and three longer (2.09 Å) Ta–O bond lengths. There are thirty-two inequivalent O2- sites. In the first O2- site, O2- is bonded in a T-shaped geometry to three Ta4+ atoms. In the second O2- site, O2- is bonded in a T-shaped geometry to three Ta4+ atoms. In the third O2- site, O2- is bonded in a T-shaped geometry to three Ta4+ atoms. In the fourth O2- site, O2- is bonded in a T-shaped geometry to three Ta4+ atoms. In the fifth O2- site, O2- is bonded in a T-shaped geometry to three Ta4+ atoms. In the sixth O2- site, O2- is bonded in a T-shaped geometry to three Ta4+ atoms. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+ and two Ta4+ atoms. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+ and two Ta4+ atoms. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+ and two Ta4+ atoms. In the tenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+ and two Ta4+ atoms. In the eleventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+ and two Ta4+ atoms. In the twelfth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+ and two Ta4+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted water-like geometry to two Ba2+ and two Ta4+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted water-like geometry to two Ba2+ and two Ta4+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted water-like geometry to two Ba2+ and two Ta4+ atoms. In the sixteenth O2- site, O2- is bonded in a distorted water-like geometry to two Ba2+ and two Ta4+ atoms. In the seventeenth O2- site, O2- is bonded in a distorted water-like geometry to two Ba2+ and two Ta4+ atoms. In the eighteenth O2- site, O2- is bonded in a distorted water-like geometry to two Ba2+ and two Ta4+ atoms. In the nineteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+ and three Ta4+ atoms. In the twentieth O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Ta4+ atoms. In the twenty-first O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+ and three Ta4+ atoms. In the twenty-second O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+ and three Ta4+ atoms. In the twenty-third O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+ and three Ta4+ atoms. In the twenty-fourth O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Ta4+ atoms. In the twenty-fifth O2- site, O2- is bonded in a 3-coordinate geometry to three Ta4+ atoms. In the twenty-sixth O2- site, O2- is bonded in a 3-coordinate geometry to three Ta4+ atoms. In the twenty-seventh O2- site, O2- is bonded in a 3-coordinate geometry to three Ta4+ atoms. In the twenty-eighth O2- site, O2- is bonded in a 3-coordinate geometry to three Ta4+ atoms. In the twenty-ninth O2- site, O2- is bonded in a 3-coordinate geometry to three Ta4+ atoms. In the thirtieth O2- site, O2- is bonded in a 3-coordinate geometry to three Ta4+ atoms. In the thirty-first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Ta4+ atoms. In the thirty-second O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Ta4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaTa4O14 by Materials Project

BaTa4O14 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Ba is bonded to eight O atoms to form BaO8 hexagonal bipyramids that share edges with six equivalent TaO6 octahedra. There are six shorter (2.75 Å) and two longer (3.02 Å) Ba–O bond lengths. There are two inequivalent Ta sites. In the first Ta site, Ta is bonded to six equivalent O atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles are 38°. All Ta–O bond lengths are 1.99 Å. In the second Ta site, Ta is bonded to six O atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and edges with two equivalent BaO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 37–38°. There is two shorter (1.99 Å) and four longer (2.00 Å) Ta–O bond length. There are three inequivalent O sites. In the first O site, O is bonded in a 2-coordinate geometry to one Ba and two equivalent Ta atoms. In the second O site, O is bonded in a bent 150 degrees geometry to two Ta atoms. In the third O site, O is bonded in a single-bond geometry to one Ba atom.

36 MATERIALS SCIENCE↗