V9PO25 crystallizes in the tetragonal I-4 space group. There are three inequivalent V sites. In the first V site, V(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form corner-sharing VO6 octahedra. The corner-sharing octahedra are not tilted. In the second V site, V(2) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms. In the third V site, V(3) is bonded to one O(3), one O(4), one O(5), one O(7), and two equivalent O(6) atoms to form distorted VO6 octahedra that share corners with two equivalent V(3)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 32°. P(1) is bonded to four equivalent O(7) atoms to form PO4 tetrahedra that share corners with four equivalent V(3)O6 octahedra. The corner-sharing octahedral tilt angles are 43°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to two equivalent V(1) atoms. In the second O site, O(2) is bonded in a linear geometry to one V(1) and one V(2) atom. In the third O site, O(3) is bonded in a linear geometry to one V(2) and one V(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one V(3) and two equivalent V(2) atoms. In the fifth O site, O(5) is bonded in a distorted linear geometry to one V(2) and one V(3) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one V(2) and two equivalent V(3) atoms. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one V(3) and one P(1) atom.
V9PO25 crystallizes in the tetragonal I-4 space group. There are three inequivalent V sites. In the first V site, V(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form corner-sharing VO6 octahedra. The corner-sharing octahedra are not tilted. Both V(1)-O(1) bond lengths are 1.82 Å. All V(1)-O(2) bond lengths are 1.92 Å. In the second V site, V(2) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms. The V(2)-O(2) bond length is 1.74 Å. The V(2)-O(3) bond length is 1.69 Å. The V(2)-O(5) bond length is 2.26 Å. The V(2)-O(6) bond length is 2.20 Å. There is one shorter (1.88 Å) and one longer (1.91 Å) V(2)-O(4) bond length. In the third V site, V(3) is bonded to one O(3), one O(4), one O(5), one O(7), and two equivalent O(6) atoms to form distorted VO6 octahedra that share corners with two equivalent V(3)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 32°. The V(3)-O(3) bond length is 1.98 Å. The V(3)-O(4) bond length is 2.25 Å. The V(3)-O(5) bond length is 1.64 Å. The V(3)-O(7) bond length is 1.91 Å. There is one shorter (1.82 Å) and one longer (1.96 Å) V(3)-O(6) bond length. P(1) is bonded to four equivalent O(7) atoms to form PO4 tetrahedra that share corners with four equivalent V(3)O6 octahedra. The corner-sharing octahedral tilt angles are 43°. All P(1)-O(7) bond lengths are 1.55 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to two equivalent V(1) atoms. In the second O site, O(2) is bonded in a linear geometry to one V(1) and one V(2) atom. In the third O site, O(3) is bonded in a linear geometry to one V(2) and one V(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one V(3) and two equivalent V(2) atoms. In the fifth O site, O(5) is bonded in a distorted linear geometry to one V(2) and one V(3) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one V(2) and two equivalent V(3) atoms. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one V(3) and one P(1) atom.