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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Na3Ca2TaO6 by Materials Project

Na3Ca2TaO6 is Caswellsilverite-derived structured and crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two equivalent TaO6 octahedra, corners with four equivalent CaO6 octahedra, edges with two equivalent TaO6 octahedra, edges with four equivalent CaO6 octahedra, and edges with six equivalent NaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–16°. There are four shorter (2.39 Å) and two longer (2.76 Å) Na–O bond lengths. In the second Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two equivalent NaO6 octahedra, corners with two equivalent CaO6 octahedra, corners with two equivalent TaO6 octahedra, edges with two equivalent TaO6 octahedra, edges with five NaO6 octahedra, and edges with five equivalent CaO6 octahedra. The corner-sharing octahedra tilt angles range from 3–17°. There are a spread of Na–O bond distances ranging from 2.41–2.60 Å. Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with four NaO6 octahedra, edges with two equivalent CaO6 octahedra, edges with three equivalent TaO6 octahedra, and edges with seven NaO6 octahedra. The corner-sharing octahedra tilt angles range from 14–18°. There are a spread of Ca–O bond distances ranging from 2.33–2.38 Å. Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six NaO6 octahedra, edges with six NaO6 octahedra, and edges with six equivalent CaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are two shorter (2.03 Å) and four longer (2.04 Å) Ta–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to three Na1+, two equivalent Ca2+, and one Ta5+ atom to form a mixture of distorted edge and corner-sharing ONa3Ca2Ta octahedra. The corner-sharing octahedra tilt angles range from 0–12°. In the second O2- site, O2- is bonded to three Na1+, two equivalent Ca2+, and one Ta5+ atom to form a mixture of distorted edge and corner-sharing ONa3Ca2Ta octahedra. The corner-sharing octahedra tilt angles range from 2–12°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na2Ca2Ta3O10 by Materials Project

Na2Ca2Ta3O10 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Na1+ is bonded in a 1-coordinate geometry to nine O2- atoms. There are a spread of Na–O bond distances ranging from 2.29–3.01 Å. Ca2+ is bonded to twelve O2- atoms to form CaO12 cuboctahedra that share corners with eight equivalent CaO12 cuboctahedra, faces with five equivalent CaO12 cuboctahedra, and faces with eight TaO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.58–2.95 Å. There are three inequivalent Ta+4.67+ sites. In the first Ta+4.67+ site, Ta+4.67+ is bonded to six O2- atoms to form distorted TaO6 octahedra that share corners with five TaO6 octahedra and faces with four equivalent CaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–17°. There are a spread of Ta–O bond distances ranging from 1.86–2.16 Å. In the second Ta+4.67+ site, Ta+4.67+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with eight equivalent CaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There is two shorter (1.97 Å) and four longer (1.99 Å) Ta–O bond length. In the third Ta+4.67+ site, Ta+4.67+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with eight equivalent CaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There is two shorter (1.97 Å) and four longer (1.99 Å) Ta–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to four equivalent Ca2+ and two Ta+4.67+ atoms. In the second O2- site, O2- is bonded to five equivalent Na1+ and one Ta+4.67+ atom to form a mixture of distorted corner and edge-sharing ONa5Ta octahedra. The corner-sharing octahedral tilt angles are 4°. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Na1+, two equivalent Ca2+, and two equivalent Ta+4.67+ atoms. In the fourth O2- site, O2- is bonded in a linear geometry to four equivalent Ca2+ and two equivalent Ta+4.67+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaCa2Ta3O10 by Materials Project

NaCa2Ta3O10 crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. Na1+ is bonded to four equivalent O2- atoms to form corner-sharing NaO4 tetrahedra. All Na–O bond lengths are 2.35 Å. Ca2+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are a spread of Ca–O bond distances ranging from 2.51–3.03 Å. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ta–O bond distances ranging from 1.80–2.31 Å. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Ta–O bond lengths are 1.97 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal planar geometry to two equivalent Na1+ and one Ta5+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to four equivalent Ca2+ and two Ta5+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent 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. In the fifth O2- site, O2- is bonded in a linear geometry to four equivalent Ca2+ and two equivalent Ta5+ atoms.

36 MATERIALS SCIENCE↗