Fe3(PO4)2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted FeO6 pentagonal pyramids that share corners with two equivalent Fe(2)O6 octahedra, corners with four equivalent Fe(1)O6 pentagonal pyramids, corners with four equivalent P(1)O4 tetrahedra,  an edgeedge with one Fe(2)O6 octahedra, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 60-66°. In the second Fe site, Fe(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share corners with four equivalent Fe(1)O6 pentagonal pyramids, corners with two equivalent P(1)O4 tetrahedra, edges with two equivalent Fe(1)O6 pentagonal pyramids, and edges with two equivalent P(1)O4 tetrahedra. P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with four equivalent Fe(1)O6 pentagonal pyramids,  an edgeedge with one Fe(2)O6 octahedra, and  an edgeedge with one Fe(1)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles are 53°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(2), and one P(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(2), and one P(1) atom. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Fe(2), two equivalent Fe(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to two equivalent Fe(1) and one P(1) atom.
Fe3(PO4)2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted FeO6 pentagonal pyramids that share corners with two equivalent Fe(2)O6 octahedra, corners with four equivalent Fe(1)O6 pentagonal pyramids, corners with four equivalent P(1)O4 tetrahedra,  an edgeedge with one Fe(2)O6 octahedra, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 60-66°. The Fe(1)-O(1) bond length is 2.10 Å. The Fe(1)-O(2) bond length is 2.17 Å. There is one shorter (2.06 Å) and one longer (2.38 Å) Fe(1)-O(3) bond length. There is one shorter (2.02 Å) and one longer (2.18 Å) Fe(1)-O(4) bond length. In the second Fe site, Fe(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share corners with four equivalent Fe(1)O6 pentagonal pyramids, corners with two equivalent P(1)O4 tetrahedra, edges with two equivalent Fe(1)O6 pentagonal pyramids, and edges with two equivalent P(1)O4 tetrahedra. Both Fe(2)-O(1) bond lengths are 2.16 Å. Both Fe(2)-O(2) bond lengths are 2.08 Å. Both Fe(2)-O(3) bond lengths are 2.20 Å. P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with four equivalent Fe(1)O6 pentagonal pyramids,  an edgeedge with one Fe(2)O6 octahedra, and  an edgeedge with one Fe(1)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles are 53°. The P(1)-O(1) bond length is 1.53 Å. The P(1)-O(2) bond length is 1.53 Å. The P(1)-O(3) bond length is 1.57 Å. The P(1)-O(4) bond length is 1.53 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(2), and one P(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(2), and one P(1) atom. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Fe(2), two equivalent Fe(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to two equivalent Fe(1) and one P(1) atom.