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DOE OSTI2020

Materials Data on Ba6Ti7Nb9O42 by Materials Project

Ba6Nb9Ti7O42 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are four 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 2.78–3.22 Å. In the second Ba2+ site, Ba2+ is bonded in a 6-coordinate geometry to twelve O2- atoms. There are a spread of Ba–O bond distances ranging from 2.81–3.28 Å. 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 2.77–3.25 Å. In the fourth 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 2.79–3.23 Å. There are five inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share a cornercorner with one TiO6 octahedra, corners with four NbO6 octahedra, and edges with two equivalent TiO6 octahedra. The corner-sharing octahedra tilt angles range from 18–42°. There are a spread of Ti–O bond distances ranging from 1.90–2.13 Å. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two equivalent NbO6 octahedra, corners with three TiO6 octahedra, and edges with two equivalent NbO6 octahedra. The corner-sharing octahedra tilt angles range from 18–44°. There are a spread of Ti–O bond distances ranging from 1.83–2.11 Å. In the third Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two equivalent TiO6 octahedra, corners with three NbO6 octahedra, and edges with two equivalent NbO6 octahedra. The corner-sharing octahedra tilt angles range from 22–43°. There are a spread of Ti–O bond distances ranging from 1.89–2.06 Å. In the fourth Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two TiO6 octahedra, corners with three NbO6 octahedra, and edges with two NbO6 octahedra. The corner-sharing octahedra tilt angles range from 21–44°. There are a spread of Ti–O bond distances ranging from 1.88–2.07 Å. In the fifth Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two TiO6 octahedra, corners with three NbO6 octahedra, an edgeedge with one TiO6 octahedra, and an edgeedge with one NbO6 octahedra. The corner-sharing octahedra tilt angles range from 21–43°. There are a spread of Ti–O bond distances ranging from 1.91–2.11 Å. There are five inequivalent Nb+4.89+ sites. In the first Nb+4.89+ site, Nb+4.89+ is bonded to six O2- atoms to form NbO6 octahedra that share a cornercorner with one TiO6 octahedra, corners with four NbO6 octahedra, and edges with two equivalent TiO6 octahedra. The corner-sharing octahedra tilt angles range from 22–44°. There are a spread of Nb–O bond distances ranging from 1.93–2.13 Å. In the second Nb+4.89+ site, Nb+4.89+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with two equivalent NbO6 octahedra and corners with four TiO6 octahedra. The corner-sharing octahedra tilt angles range from 37–43°. There are a spread of Nb–O bond distances ranging from 1.97–2.08 Å. In the third Nb+4.89+ site, Nb+4.89+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with three TiO6 octahedra and corners with three NbO6 octahedra. The corner-sharing octahedra tilt angles range from 35–43°. There are a spread of Nb–O bond distances ranging from 1.96–2.07 Å. In the fourth Nb+4.89+ site, Nb+4.89+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with two TiO6 octahedra, corners with three NbO6 octahedra, and edges with two TiO6 octahedra. The corner-sharing octahedra tilt angles range from 21–45°. There are a spread of Nb–O bond distances ranging from 1.93–2.13 Å. In the fifth Nb+4.89+ site, Nb+4.89+ is bonded to six O2- atoms to form NbO6 octahedra that share a cornercorner with one TiO6 octahedra, corners with four NbO6 octahedra, and edges with two TiO6 octahedra. The corner-sharing octahedra tilt angles range from 21–44°. There are a spread of Nb–O bond distances ranging from 1.92–2.13 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Ti4+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+, one Ti4+, and two equivalent Nb+4.89+ atoms. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ba2+ and two Ti4+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Ba2+, one Ti4+, and one Nb+4.89+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to two Ba2+, one Ti4+, and one Nb+4.89+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Ba2+, one Ti4+, and one Nb+4.89+ atom. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+, two equivalent Ti4+, and one Nb+4.89+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+, one Ti4+, and two equivalent Nb+4.89+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to two Ba2+, one Ti4+, and one Nb+4.89+ atom. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to two Ba2+ and two Nb+4.89+ atoms. In the eleventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Ba2+, one Ti4+, and one Nb+4.89+ atom. In the twelfth O2- site, O2- is bonded in a 2-coordinate geometry to two Ba2+ and two Nb+4.89+ atoms. In the thirteenth O2- site, O2- is bonded in a 2-coordinate geometry to two Ba2+ and two Nb+4.89+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Ba2+, one Ti4+, and one Nb+4.89+ atom. In the fifteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ba2+, one Ti4+, and one Nb+4.89+ atom. In the sixteenth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+ and two Nb+4.89+ atoms. In the seventeenth O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+, two Ti4+, and one Nb+4.89+ atom. In the eighteenth O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+, one Ti4+, and two Nb+4.89+ atoms. In the nineteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Ba2+, one Ti4+, and one Nb+4.89+ atom. In the twentieth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ba2+, one Ti4+, and one Nb+4.89+ atom. In the twenty-first O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+ and two Nb+4.89+ atoms. In the twenty-second O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+, two Ti4+, and one Nb+4.89+ atom. In the twenty-third O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+, two Ti4+, and one Nb+4.89+ atom. In the twenty-fourth O2- site, O2- is bonded in a bent 150 degrees geometry to two Ba2+, one Ti4+, and one Nb+4.89+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba7Ti2Nb4O21 by Materials Project

Ba7Ti2Nb4O21 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are four 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 three equivalent BaO12 cuboctahedra, faces with three equivalent TiO6 octahedra, and faces with four NbO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.73–3.06 Å. In the second 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 2.81–3.23 Å. In the third Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine equivalent BaO12 cuboctahedra, faces with six BaO12 cuboctahedra, faces with three equivalent TiO6 octahedra, and faces with five NbO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.83–2.98 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 equivalent BaO12 cuboctahedra, faces with two equivalent TiO6 octahedra, and faces with six equivalent NbO6 octahedra. There are six shorter (2.91 Å) and six longer (2.93 Å) Ba–O bond lengths. Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six NbO6 octahedra and faces with seven BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 8–12°. There are three shorter (1.87 Å) and three longer (2.24 Å) Ti–O bond lengths. There are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted NbO6 octahedra that share corners with three equivalent TiO6 octahedra and faces with four BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 12°. There are three shorter (1.87 Å) and three longer (2.30 Å) Nb–O bond lengths. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with three equivalent TiO6 octahedra, corners with three equivalent NbO6 octahedra, and faces with eight BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–8°. There are three shorter (1.97 Å) and three longer (2.13 Å) Nb–O bond lengths. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to four Ba2+, one Ti4+, and one Nb5+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+, one Ti4+, and one Nb5+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to four Ba2+ and one Nb5+ atom. In the fourth O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two equivalent Nb5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba8Ti3Nb4O24 by Materials Project

Ba8Ti3Nb4O24 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 twelve BaO12 cuboctahedra, faces with three equivalent BaO12 cuboctahedra, and faces with five NbO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.94–3.09 Å. In the second 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, a faceface with one NbO6 octahedra, and faces with seven TiO6 octahedra. There are three shorter (2.91 Å) and nine longer (2.93 Å) Ba–O bond lengths. In the third 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, faces with four TiO6 octahedra, and faces with four NbO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.86–2.93 Å. In the fourth Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form distorted BaO12 cuboctahedra that share corners with twelve BaO12 cuboctahedra, faces with three equivalent BaO12 cuboctahedra, a faceface with one TiO6 octahedra, and faces with six NbO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.68–3.18 Å. In the fifth Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, corners with three equivalent TiO6 octahedra, faces with seven BaO12 cuboctahedra, a faceface with one NbO6 octahedra, and faces with six TiO6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are a spread of Ba–O bond distances ranging from 2.88–3.03 Å. In the sixth 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, a faceface with one TiO6 octahedra, and faces with six NbO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.77–2.99 Å. In the seventh Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are three shorter (2.76 Å) and six longer (2.99 Å) Ba–O bond lengths. In the eighth 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 TiO6 octahedra, faces with seven BaO12 cuboctahedra, faces with three equivalent TiO6 octahedra, and faces with four NbO6 octahedra. The corner-sharing octahedral tilt angles are 8°. There are a spread of Ba–O bond distances ranging from 2.90–3.01 Å. There are three inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent TiO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one TiO6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are three shorter (1.98 Å) and three longer (2.03 Å) Ti–O bond lengths. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent NbO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one TiO6 octahedra. The corner-sharing octahedral tilt angles are 8°. There are three shorter (1.95 Å) and three longer (2.05 Å) Ti–O bond lengths. In the third Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with three equivalent TiO6 octahedra, corners with three equivalent NbO6 octahedra, and faces with eight BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 1°. There are three shorter (2.01 Å) and three longer (2.04 Å) Ti–O bond lengths. There are four inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted NbO6 octahedra that share corners with three equivalent NbO6 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 (2.28 Å) Nb–O bond lengths. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with three equivalent NbO6 octahedra and faces with five BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 10°. There are three shorter (1.87 Å) and three longer (2.25 Å) Nb–O bond lengths. In the third Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with three equivalent TiO6 octahedra, corners with three equivalent NbO6 octahedra, and faces with seven BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 8–10°. There are three shorter (1.94 Å) and three longer (2.13 Å) Nb–O bond lengths. In the fourth Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with three equivalent TiO6 octahedra, corners with three equivalent NbO6 octahedra, and faces with eight BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 1–7°. There are three shorter (1.99 Å) and three longer (2.09 Å) Nb–O bond lengths. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two Ti4+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+ and two Nb5+ atoms. In the third O2- site, O2- is bonded in a distorted single-bond geometry to four Ba2+ and one Nb5+ atom. In the fourth O2- site, O2- is bonded in a distorted linear geometry to four Ba2+, one Ti4+, and one Nb5+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to four Ba2+ and one Nb5+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+ and two Ti4+ atoms. In the seventh O2- site, O2- is bonded in a distorted linear geometry to four Ba2+, one Ti4+, and one Nb5+ atom. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to three Ba2+ and two Nb5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba3TiNb4O15 by Materials Project

Ba3TiNb4O15 crystallizes in the monoclinic Pc 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 faces with two equivalent BaO12 cuboctahedra, faces with two equivalent TiO6 octahedra, and faces with six NbO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.74–2.98 Å. In the second Ba2+ site, Ba2+ is bonded in a 6-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.80–3.22 Å. In the third Ba2+ site, Ba2+ is bonded in a 6-coordinate geometry to eleven O2- atoms. There are a spread of Ba–O bond distances ranging from 2.85–3.33 Å. Ti4+ is bonded to six O2- atoms to form distorted TiO6 octahedra that share corners with two equivalent TiO6 octahedra, corners with four NbO6 octahedra, and faces with two equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 5–40°. There are a spread of Ti–O bond distances ranging from 1.76–2.36 Å. There are four inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six NbO6 octahedra and faces with two equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 8–40°. There are a spread of Nb–O bond distances ranging from 1.88–2.26 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share a cornercorner with one TiO6 octahedra, corners with five NbO6 octahedra, and faces with two equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 2–40°. There are a spread of Nb–O bond distances ranging from 1.89–2.23 Å. In the third Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with two equivalent TiO6 octahedra, corners with four NbO6 octahedra, and faces with two equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 6–40°. There are a spread of Nb–O bond distances ranging from 1.89–2.24 Å. In the fourth Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share a cornercorner with one TiO6 octahedra and corners with five NbO6 octahedra. The corner-sharing octahedra tilt angles range from 4–38°. There are a spread of Nb–O bond distances ranging from 1.86–2.27 Å. There are fifteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to two Ba2+ and two equivalent Ti4+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two Ba2+ and two equivalent Nb5+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two Ba2+ and two equivalent Nb5+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to two Ba2+ and two equivalent Nb5+ atoms. In the fifth O2- site, O2- is bonded in a distorted linear geometry to two Ba2+ and two equivalent Nb5+ atoms. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ba2+ and two Nb5+ atoms. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ba2+ and two Nb5+ atoms. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ba2+, one Ti4+, and one Nb5+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ba2+ and two Nb5+ atoms. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+, one Ti4+, and one Nb5+ atom. In the eleventh O2- site, O2- is bonded in a distorted linear geometry to two equivalent Ba2+ and two Nb5+ atoms. In the twelfth O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+, one Ti4+, and one Nb5+ atom. In the thirteenth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+ and two Nb5+ atoms. In the fourteenth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+, one Ti4+, and one Nb5+ atom. In the fifteenth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+ and two Nb5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba2Ti3Nb4O18 by Materials Project

Ba2Ti3Nb4O18 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with three NbO6 octahedra, corners with four TiO6 octahedra, edges with two equivalent BaO12 cuboctahedra, edges with two NbO6 octahedra, edges with three TiO6 octahedra, a faceface with one BaO12 cuboctahedra, and faces with three NbO6 octahedra. The corner-sharing octahedra tilt angles range from 33–54°. There are a spread of Ba–O bond distances ranging from 2.85–3.11 Å. There are two inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with four equivalent BaO12 cuboctahedra, corners with two equivalent TiO6 octahedra, corners with two equivalent NbO6 octahedra, edges with two equivalent BaO12 cuboctahedra, and edges with two equivalent NbO6 octahedra. The corner-sharing octahedra tilt angles range from 46–50°. There are a spread of Ti–O bond distances ranging from 1.93–2.01 Å. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted TiO6 octahedra that share corners with two equivalent BaO12 cuboctahedra, a cornercorner with one TiO6 octahedra, corners with three NbO6 octahedra, edges with two equivalent BaO12 cuboctahedra, an edgeedge with one TiO6 octahedra, and edges with two equivalent NbO6 octahedra. The corner-sharing octahedra tilt angles range from 38–54°. There are a spread of Ti–O bond distances ranging from 1.83–2.21 Å. There are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted NbO6 octahedra that share a cornercorner with one BaO12 cuboctahedra, corners with two TiO6 octahedra, corners with three NbO6 octahedra, an edgeedge with one BaO12 cuboctahedra, an edgeedge with one TiO6 octahedra, and faces with two equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 43–50°. There are a spread of Nb–O bond distances ranging from 1.86–2.27 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted NbO6 octahedra that share corners with two equivalent BaO12 cuboctahedra, corners with two equivalent TiO6 octahedra, corners with three NbO6 octahedra, an edgeedge with one BaO12 cuboctahedra, edges with two equivalent TiO6 octahedra, and a faceface with one BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 38–54°. There are a spread of Nb–O bond distances ranging from 1.91–2.26 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ba2+, two equivalent Ti4+, and one Nb5+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent Ba2+, one Ti4+, and one Nb5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+, one Ti4+, and two equivalent Nb5+ atoms. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ba2+ and two equivalent Nb5+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+ and two Nb5+ atoms. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+, one Ti4+, and one Nb5+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to two Ti4+ and one Nb5+ atom. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+, one Ti4+, and one Nb5+ atom. In the ninth O2- site, O2- is bonded in a distorted water-like geometry to two equivalent Ba2+, one Ti4+, and one Nb5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba4TiNb9O18 by Materials Project

Ba4TiNb9O18 crystallizes in the tetragonal P4/mmm 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 corners with eight equivalent BaO12 cuboctahedra, faces with five equivalent BaO12 cuboctahedra, faces with four equivalent NbO6 octahedra, and faces with four equivalent NbO5 square pyramids. There are a spread of Ba–O bond distances ranging from 2.89–2.98 Å. In the second Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with eight equivalent BaO12 cuboctahedra, faces with five equivalent BaO12 cuboctahedra, faces with four equivalent TiO6 octahedra, and faces with four equivalent NbO5 square pyramids. There are a spread of Ba–O bond distances ranging from 2.85–3.00 Å. Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with four equivalent TiO6 octahedra, corners with two equivalent NbO5 square pyramids, and faces with eight equivalent BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (1.97 Å) and four longer (2.10 Å) Ti–O bond lengths. There are four inequivalent Nb+2.67+ sites. In the first Nb+2.67+ site, Nb+2.67+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Nb–O bond distances ranging from 2.11–2.16 Å. In the second Nb+2.67+ site, Nb+2.67+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with four equivalent NbO6 octahedra, corners with two equivalent NbO5 square pyramids, and faces with eight equivalent BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.01 Å) and four longer (2.10 Å) Nb–O bond lengths. In the third Nb+2.67+ site, Nb+2.67+ is bonded to five O2- atoms to form NbO5 square pyramids that share a cornercorner with one NbO6 octahedra, corners with four equivalent NbO5 square pyramids, and faces with four equivalent BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.11 Å) and one longer (2.17 Å) Nb–O bond lengths. In the fourth Nb+2.67+ site, Nb+2.67+ is bonded to five O2- atoms to form NbO5 square pyramids that share a cornercorner with one TiO6 octahedra, corners with four equivalent NbO5 square pyramids, and faces with four equivalent BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.11 Å) and one longer (2.14 Å) Nb–O bond lengths. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Ba2+ and three Nb+2.67+ atoms to form a mixture of distorted edge and corner-sharing OBa2Nb3 trigonal bipyramids. In the second O2- site, O2- is bonded in a distorted T-shaped geometry to two equivalent Ba2+ and three Nb+2.67+ atoms. In the third O2- site, O2- is bonded to four equivalent Ba2+ and two equivalent Ti4+ atoms to form a mixture of distorted edge, corner, and face-sharing OBa4Ti2 octahedra. The corner-sharing octahedral tilt angles are 0°. In the fourth O2- site, O2- is bonded in a distorted linear geometry to four equivalent Ba2+ and two equivalent Nb+2.67+ atoms. In the fifth O2- site, O2- is bonded in a distorted linear geometry to four equivalent Ba2+ and two Nb+2.67+ atoms. In the sixth O2- site, O2- is bonded in a distorted linear geometry to four equivalent Ba2+, one Ti4+, and one Nb+2.67+ atom. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to four equivalent Nb+2.67+ atoms.

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