Materials Data on Ba7Ti2Nb4O21 by Materials Project

Dataset · Thu Apr 30 04:00:00 EDT 2020

DOI:https://doi.org/10.17188/1691315· OSTI ID:1691315

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.

• Research Organization: LBNL Materials Project; Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• Contributing Organization: The Materials Project; MIT; UC Berkeley; Duke; U Louvain
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 1691315
• Report Number(s): mp-1228174
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Ba-Nb-O-Ti
Ba7Ti2Nb4O21
crystal structure