Materials Data on Ta7(P2O7)8 by Materials Project
Ta7(P2O7)8 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. there are three inequivalent Ta+4.57+ sites. In the first Ta+4.57+ site, Ta+4.57+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Ta–O bond distances ranging from 1.96–2.03 Å. In the second Ta+4.57+ site, Ta+4.57+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six PO4 tetrahedra. There is two shorter (1.96 Å) and four longer (2.02 Å) Ta–O bond length. In the third Ta+4.57+ site, Ta+4.57+ is bonded to six equivalent O2- atoms to form TaO6 octahedra that share corners with six equivalent PO4 tetrahedra. All Ta–O bond lengths are 2.00 Å. There are four inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three TaO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 12–15°. There are a spread of P–O bond distances ranging from 1.52–1.55 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two TaO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 4–18°. There are a spread of P–O bond distances ranging from 1.46–1.64 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three equivalent TaO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 13°. There is three shorter (1.52 Å) and one longer (1.59 Å) P–O bond length. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three equivalent TaO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 14°. There is three shorter (1.52 Å) and one longer (1.59 Å) P–O bond length. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to two P5+ atoms. In the second O2- site, O2- is bonded in a linear geometry to two P5+ atoms. In the third O2- site, O2- is bonded in a linear geometry to one Ta+4.57+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a linear geometry to one Ta+4.57+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a linear geometry to one Ta+4.57+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ta+4.57+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a linear geometry to one Ta+4.57+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the ninth O2- site, O2- is bonded in a linear geometry to one Ta+4.57+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a linear geometry to one Ta+4.57+ and one P5+ atom.