Mn4(PO4)3 crystallizes in the trigonal R3c space group. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form distorted MnO6 pentagonal pyramids that share corners with six equivalent Mn(2)O5 square pyramids and corners with six equivalent P(1)O4 tetrahedra. In the second Mn site, Mn(2) is bonded to one O(1), one O(3), one O(4), and two equivalent O(2) atoms to form distorted MnO5 square pyramids that share corners with two equivalent Mn(1)O6 pentagonal pyramids, corners with two equivalent Mn(2)O5 square pyramids, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one 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 corners with two equivalent Mn(1)O6 pentagonal pyramids, corners with three equivalent Mn(2)O5 square pyramids, and  an edgeedge with one Mn(2)O5 square pyramid. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Mn(1), one Mn(2), and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Mn(2) and one P(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Mn(2) and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Mn(1), one Mn(2), and one P(1) atom.
Mn4(PO4)3 crystallizes in the trigonal R3c space group. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form distorted MnO6 pentagonal pyramids that share corners with six equivalent Mn(2)O5 square pyramids and corners with six equivalent P(1)O4 tetrahedra. All Mn(1)-O(1) bond lengths are 2.38 Å. All Mn(1)-O(4) bond lengths are 2.21 Å. In the second Mn site, Mn(2) is bonded to one O(1), one O(3), one O(4), and two equivalent O(2) atoms to form distorted MnO5 square pyramids that share corners with two equivalent Mn(1)O6 pentagonal pyramids, corners with two equivalent Mn(2)O5 square pyramids, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one P(1)O4 tetrahedra. The Mn(2)-O(1) bond length is 2.13 Å. The Mn(2)-O(3) bond length is 2.04 Å. The Mn(2)-O(4) bond length is 2.14 Å. There is one shorter (2.06 Å) and one longer (2.18 Å) Mn(2)-O(2) bond length. 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 corners with two equivalent Mn(1)O6 pentagonal pyramids, corners with three equivalent Mn(2)O5 square pyramids, and  an edgeedge with one Mn(2)O5 square pyramid. The P(1)-O(1) bond length is 1.57 Å. The P(1)-O(2) bond length is 1.57 Å. The P(1)-O(3) bond length is 1.51 Å. The P(1)-O(4) bond length is 1.57 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Mn(1), one Mn(2), and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Mn(2) and one P(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Mn(2) and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Mn(1), one Mn(2), and one P(1) atom.