DOE OSTI2020
TaOPO4 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with two equivalent TaO6 octahedra and corners with four PO4 tetrahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Ta–O bond distances ranging from 1.91–2.04 Å. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with two equivalent TaO6 octahedra and corners with four PO4 tetrahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Ta–O bond distances ranging from 1.91–2.05 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four TaO6 octahedra. The corner-sharing octahedra tilt angles range from 10–19°. There are a spread of P–O bond distances ranging from 1.53–1.55 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four TaO6 octahedra. The corner-sharing octahedra tilt angles range from 12–27°. There is two shorter (1.53 Å) and two longer (1.54 Å) P–O bond length. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to one Ta5+ and one P5+ atom. In the second O2- site, O2- is bonded in a linear geometry to one Ta5+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted linear geometry to one Ta5+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a linear geometry to one Ta5+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a linear geometry to two equivalent Ta5+ atoms. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ta5+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a linear geometry to two equivalent Ta5+ atoms. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ta5+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a linear geometry to one Ta5+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a linear geometry to one Ta5+ and one P5+ atom.