Materials Data on TbTa3O9 by Materials Project
TbTa3O9 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are two inequivalent Tb3+ sites. In the first Tb3+ site, Tb3+ is bonded to twelve O2- atoms to form distorted TbO12 cuboctahedra that share corners with three TbO12 cuboctahedra, faces with two equivalent TbO12 cuboctahedra, and faces with eight TaO6 octahedra. There are a spread of Tb–O bond distances ranging from 2.46–2.96 Å. In the second Tb3+ site, Tb3+ is bonded to twelve O2- atoms to form distorted TbO12 cuboctahedra that share corners with three TbO12 cuboctahedra, faces with two equivalent TbO12 cuboctahedra, and faces with eight TaO6 octahedra. There are a spread of Tb–O bond distances ranging from 2.43–2.95 Å. There are six 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 TbO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 1–19°. There are a spread of Ta–O bond distances ranging from 1.91–2.07 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 two TbO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 1–15°. There are a spread of Ta–O bond distances ranging from 1.95–2.00 Å. In the third Ta5+ site, Ta5+ is bonded to six O2- atoms to form distorted TaO6 octahedra that share corners with six TaO6 octahedra and faces with three TbO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 3–19°. There are a spread of Ta–O bond distances ranging from 1.90–2.11 Å. In the fourth Ta5+ site, Ta5+ is bonded to six O2- atoms to form distorted TaO6 octahedra that share corners with six TaO6 octahedra and faces with three TbO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 2–18°. There are a spread of Ta–O bond distances ranging from 1.90–2.11 Å. In the fifth Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with three TbO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 1–18°. There are a spread of Ta–O bond distances ranging from 1.92–2.07 Å. In the sixth Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with two TbO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 1–16°. There are a spread of Ta–O bond distances ranging from 1.96–2.00 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to two Tb3+ and two Ta5+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Tb3+ and two Ta5+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Tb3+ and two Ta5+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two Tb3+ and two Ta5+ atoms. In the fifth O2- site, O2- is bonded in a 5-coordinate geometry to three Tb3+ and two Ta5+ atoms. In the sixth O2- site, O2- is bonded in a 5-coordinate geometry to three Tb3+ and two Ta5+ atoms. In the seventh O2- site, O2- is bonded in a linear geometry to two Ta5+ atoms. In the eighth O2- site, O2- is bonded in a linear geometry to two Ta5+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to one Tb3+ and two Ta5+ atoms. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to two Tb3+ and two Ta5+ atoms. In the eleventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Tb3+ and two Ta5+ atoms. In the twelfth O2- site, O2- is bonded in a 2-coordinate geometry to one Tb3+ and two Ta5+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted linear geometry to one Tb3+ and two Ta5+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted linear geometry to one Tb3+ and two Ta5+ atoms. In the fifteenth O2- site, O2- is bonded in a linear geometry to two Ta5+ atoms. In the sixteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Tb3+ and two Ta5+ atoms. In the seventeenth O2- site, O2- is bonded in a 2-coordinate geometry to one Tb3+ and two Ta5+ atoms. In the eighteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Tb3+ and two Ta5+ atoms.