Materials Data on Ta9As2O25 by Materials Project
Ta9As2O25 crystallizes in the tetragonal I4/m space group. The structure is three-dimensional. there are three inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (1.99 Å) and four longer (2.02 Å) Ta–O bond lengths. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–29°. There are a spread of Ta–O bond distances ranging from 1.86–2.34 Å. In the third Ta5+ site, Ta5+ is bonded to six O2- atoms to form distorted TaO6 octahedra that share corners with four TaO6 octahedra, corners with two equivalent AsO4 tetrahedra, and edges with two equivalent TaO6 octahedra. The corner-sharing octahedra tilt angles range from 7–29°. There are a spread of Ta–O bond distances ranging from 1.87–2.33 Å. As+2.50+ is bonded to four equivalent O2- atoms to form distorted AsO4 tetrahedra that share corners with four equivalent TaO6 octahedra and edges with two equivalent AsO4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. All As–O bond lengths are 2.07 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Ta5+ and two equivalent As+2.50+ atoms. In the second O2- site, O2- is bonded in a linear geometry to two Ta5+ atoms. The O–Ta bond length is 1.86 Å. In the third O2- site, O2- is bonded in a linear geometry to two equivalent Ta5+ atoms. In the fourth O2- site, O2- is bonded in a linear geometry to two Ta5+ atoms. In the fifth O2- site, O2- is bonded in a linear geometry to two Ta5+ atoms. The O–Ta bond length is 1.86 Å. In the sixth O2- site, O2- is bonded in a linear geometry to two Ta5+ atoms. There is one shorter (1.86 Å) and one longer (2.02 Å) O–Ta bond length. 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 3-coordinate geometry to three Ta5+ atoms. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to three Ta5+ atoms. In the tenth O2- site, O2- is bonded in a linear geometry to two Ta5+ atoms.