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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Ca2Ta2O7 by Materials Project

Ca2Ta2O7 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Ca2+ is bonded to eight O2- atoms to form distorted CaO8 hexagonal bipyramids that share edges with six equivalent CaO8 hexagonal bipyramids and edges with six equivalent TaO6 octahedra. There are two shorter (2.28 Å) and six longer (2.68 Å) Ca–O bond lengths. Ta5+ is bonded to six equivalent O2- atoms to form TaO6 octahedra that share corners with six equivalent TaO6 octahedra and edges with six equivalent CaO8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 41°. All Ta–O bond lengths are 1.99 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded to four equivalent Ca2+ atoms to form corner-sharing OCa4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaTa2O6 by Materials Project

CaTa2O6 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.44–2.59 Å. 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 28–45°. There are a spread of Ta–O bond distances ranging from 1.92–2.15 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ca2+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+ and two equivalent Ta5+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+ and two equivalent Ta5+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+ and two equivalent Ta5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaTa4O11 by Materials Project

CaTa4O11 crystallizes in the hexagonal P6_322 space group. The structure is three-dimensional. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are six shorter (2.48 Å) and two longer (2.68 Å) Ca–O bond lengths. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded in an octahedral geometry to six equivalent O2- atoms. All Ta–O bond lengths are 2.00 Å. In the second Ta5+ site, Ta5+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ta–O bond distances ranging from 1.98–2.50 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+ and three equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to three equivalent Ta5+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+ and two Ta5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaTa2O6 by Materials Project

CaTa2O6 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ca2+ is bonded to twelve equivalent O2- atoms to form CaO12 cuboctahedra that share corners with twelve equivalent CaO12 cuboctahedra and faces with eight equivalent TaO6 octahedra. All Ca–O bond lengths are 2.80 Å. Ta5+ is bonded to six equivalent O2- atoms to form TaO6 octahedra that share corners with six equivalent TaO6 octahedra and faces with four equivalent CaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Ta–O bond lengths are 1.98 Å. O2- is bonded in a distorted linear geometry to two equivalent Ca2+ and two equivalent Ta5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaTa2O6 by Materials Project

CaTa2O6 crystallizes in the cubic Pm-3 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 4-coordinate geometry to eight O2- atoms. There are four shorter (2.38 Å) and four longer (2.81 Å) Ca–O bond lengths. In the second Ca2+ site, Ca2+ is bonded to twelve equivalent O2- atoms to form CaO12 cuboctahedra that share faces with eight equivalent TaO6 octahedra. All Ca–O bond lengths are 2.77 Å. Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six equivalent TaO6 octahedra and a faceface with one CaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 16–23°. There is three shorter (1.99 Å) and three longer (2.00 Å) Ta–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted T-shaped geometry to one Ca2+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two Ca2+ and two equivalent Ta5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca4Ta2O9 by Materials Project

Ca3(CaTa2)O9 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are five inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 3-coordinate geometry to five O2- atoms. There are a spread of Ca–O bond distances ranging from 2.33–2.86 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six equivalent CaO6 octahedra and corners with six equivalent TaO6 octahedra. The corner-sharing octahedra tilt angles range from 41–62°. There are two shorter (2.37 Å) and four longer (2.38 Å) Ca–O bond lengths. In the third Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six equivalent TaO6 octahedra. The corner-sharing octahedra tilt angles range from 35–37°. There are a spread of Ca–O bond distances ranging from 2.29–2.31 Å. In the fourth Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted CaO6 octahedra that share corners with three equivalent CaO6 octahedra, corners with three equivalent TaO6 octahedra, and edges with three equivalent TaO6 octahedra. The corner-sharing octahedra tilt angles range from 29–62°. There are a spread of Ca–O bond distances ranging from 2.34–2.43 Å. In the fifth Ca2+ site, Ca2+ is bonded in a distorted trigonal planar geometry to three O2- atoms. All Ca–O bond lengths are 2.25 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 CaO6 octahedra and a faceface with one TaO6 octahedra. The corner-sharing octahedra tilt angles range from 29–37°. There are a spread of Ta–O bond distances ranging from 1.92–2.12 Å. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form distorted TaO6 octahedra that share corners with three equivalent CaO6 octahedra, edges with three equivalent CaO6 octahedra, and a faceface with one TaO6 octahedra. The corner-sharing octahedra tilt angles range from 41–42°. There are a spread of Ta–O bond distances ranging from 1.90–2.21 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+ and two Ta5+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+ and one Ta5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two Ca2+ and one Ta5+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Ta5+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to two Ca2+ and one Ta5+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+ and two Ta5+ atoms. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+ and two Ta5+ atoms. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to two Ca2+ and one Ta5+ atom. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Ta5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca3Ta2O8 by Materials Project

Ca3Ta2O8 crystallizes in the orthorhombic Cmce space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six equivalent TaO4 tetrahedra and edges with four CaO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.28–2.47 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six equivalent TaO4 tetrahedra and edges with four equivalent CaO6 octahedra. There are two shorter (2.34 Å) and four longer (2.41 Å) Ca–O bond lengths. Ta5+ is bonded to four O2- atoms to form TaO4 tetrahedra that share corners with nine CaO6 octahedra. The corner-sharing octahedra tilt angles range from 49–56°. There are a spread of Ta–O bond distances ranging from 1.86–1.92 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two Ca2+ and one Ta5+ atom. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Ca2+ and one Ta5+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Ca2+ and one Ta5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca5Ta4O15 by Materials Project

Ca5Ta4O15 crystallizes in the trigonal P-3c1 space group. The structure is three-dimensional. there are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six equivalent O2- atoms. There are three shorter (2.42 Å) and three longer (2.43 Å) Ca–O bond lengths. In the second Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are three shorter (2.41 Å) and three longer (2.49 Å) Ca–O bond lengths. In the third Ca2+ site, Ca2+ is bonded to twelve O2- atoms to form CaO12 cuboctahedra that share corners with six equivalent CaO12 cuboctahedra and faces with eight TaO6 octahedra. There are six shorter (2.75 Å) and six longer (2.77 Å) Ca–O bond lengths. 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 three equivalent CaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–22°. There is three shorter (1.97 Å) and three longer (2.01 Å) Ta–O bond length. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three equivalent TaO6 octahedra and a faceface with one CaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 22°. There are three shorter (1.91 Å) and three longer (2.13 Å) Ta–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Ta5+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+ and two Ta5+ atoms. In the third O2- site, O2- is bonded in a distorted linear geometry to two equivalent Ca2+ and two equivalent Ta5+ atoms.

36 MATERIALS SCIENCE↗