DOE OSTI2020
Na4Cr3Al(P2O7)4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.33–3.06 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.33–2.65 Å. In the third Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.33–2.89 Å. In the fourth Na1+ site, Na1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.38–3.03 Å. There are three inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Cr–O bond distances ranging from 1.96–2.05 Å. In the second Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Cr–O bond distances ranging from 1.96–2.05 Å. In the third Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Cr–O bond distances ranging from 1.98–2.08 Å. Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.88–1.98 Å. There are eight inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three CrO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 34–55°. There are a spread of P–O bond distances ranging from 1.52–1.63 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one AlO6 octahedra, corners with two CrO6 octahedra, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 34–55°. There are a spread of P–O bond distances ranging from 1.52–1.63 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one AlO6 octahedra, corners with two CrO6 octahedra, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 33–53°. There are a spread of P–O bond distances ranging from 1.52–1.63 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one AlO6 octahedra, corners with two CrO6 octahedra, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 32–54°. There are a spread of P–O bond distances ranging from 1.52–1.64 Å. In the fifth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one AlO6 octahedra, corners with two CrO6 octahedra, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 21–51°. There are a spread of P–O bond distances ranging from 1.51–1.63 Å. In the sixth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three CrO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 21–51°. There are a spread of P–O bond distances ranging from 1.51–1.62 Å. In the seventh P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one AlO6 octahedra, corners with two CrO6 octahedra, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 20–47°. There are a spread of P–O bond distances ranging from 1.51–1.62 Å. In the eighth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one AlO6 octahedra, corners with two CrO6 octahedra, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 18–51°. There are a spread of P–O bond distances ranging from 1.51–1.63 Å. There are twenty-eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+ and two P5+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+ and two P5+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+ and two P5+ atoms. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+ and two P5+ atoms. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Cr3+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one Al3+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Cr3+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Cr3+, and one P5+ atom. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to two Na1+, one Cr3+, and one P5+ atom. In the tenth O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, one Cr3+, and one P5+ atom. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Al3+, and one P5+ atom. In the twelfth O2- site, O2- is bonded in a 3-coordinate geometry to two Na1+, one Cr3+, and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Cr3+, and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Cr3+, and one P5+ atom. In the fifteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Al3+, and one P5+ atom. In the sixteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Cr3+, and one P5+ atom. In the seventeenth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Al3+, and one P5+ atom. In the eighteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Cr3+, and one P5+ atom. In the nineteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Cr3+, and one P5+ atom. In the twentieth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Cr3+, and one P5+ atom. In the twenty-first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cr3+ and one P5+ atom. In the twenty-second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Na1+, one Cr3+, and one P5+ atom. In the twenty-third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Na1+, one Cr3+, and one P5+ atom. In the twenty-fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Al3+ and one P5+ atom. In the twenty-fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Cr3+, and one P5+ atom. In the twenty-sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Cr3+, and one P5+ atom. In the twenty-seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Cr3+, and one P5+ atom. In the twenty-eighth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Al3+, and one P5+ atom.