Sb(PO3)4 crystallizes in the monoclinic C2/c space group. Sb(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form SbO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra and corners with four equivalent P(1)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with two equivalent Sb(1)O6 octahedra and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 24-42°. In the second P site, P(2) is bonded to one O(2), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Sb(1)O6 octahedra and corners with two equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 45°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Sb(1) and one P(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to one P(2) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Sb(1) and one P(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Sb(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom.
Sb(PO3)4 crystallizes in the monoclinic C2/c space group. Sb(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form SbO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra and corners with four equivalent P(1)O4 tetrahedra. Both Sb(1)-O(1) bond lengths are 2.16 Å. Both Sb(1)-O(3) bond lengths are 2.07 Å. Both Sb(1)-O(4) bond lengths are 2.08 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with two equivalent Sb(1)O6 octahedra and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 24-42°. The P(1)-O(1) bond length is 1.49 Å. The P(1)-O(4) bond length is 1.51 Å. The P(1)-O(5) bond length is 1.58 Å. The P(1)-O(6) bond length is 1.57 Å. In the second P site, P(2) is bonded to one O(2), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Sb(1)O6 octahedra and corners with two equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 45°. The P(2)-O(2) bond length is 1.45 Å. The P(2)-O(3) bond length is 1.52 Å. The P(2)-O(5) bond length is 1.61 Å. The P(2)-O(6) bond length is 1.61 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Sb(1) and one P(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to one P(2) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Sb(1) and one P(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Sb(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom.