Mn2PO4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(2), one O(3), and four equivalent O(1) atoms to form distorted MnO6 pentagonal pyramids that share corners with four equivalent Mn(2)O6 octahedra, corners with four equivalent Mn(1)O6 pentagonal pyramids, corners with four equivalent P(1)O4 tetrahedra, edges with two equivalent Mn(2)O6 octahedra, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 62-83°. In the second Mn site, Mn(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted MnO6 octahedra that share corners with four equivalent Mn(1)O6 pentagonal pyramids, corners with two equivalent P(1)O4 tetrahedra, edges with two equivalent Mn(2)O6 octahedra, edges with two equivalent Mn(1)O6 pentagonal pyramids, and edges with two equivalent P(1)O4 tetrahedra. P(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form PO4 tetrahedra that share corners with two equivalent Mn(2)O6 octahedra, corners with four equivalent Mn(1)O6 pentagonal pyramids, edges with two equivalent Mn(2)O6 octahedra, and  an edgeedge with one Mn(1)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles are 61°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Mn(2), two equivalent Mn(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Mn(1), two equivalent Mn(2), and one P(1) atom. In the third O site, O(3) is bonded to one Mn(1), two equivalent Mn(2), and one P(1) atom to form distorted corner-sharing OMn3P tetrahedra.
Mn2PO4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(2), one O(3), and four equivalent O(1) atoms to form distorted MnO6 pentagonal pyramids that share corners with four equivalent Mn(2)O6 octahedra, corners with four equivalent Mn(1)O6 pentagonal pyramids, corners with four equivalent P(1)O4 tetrahedra, edges with two equivalent Mn(2)O6 octahedra, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 62-83°. The Mn(1)-O(2) bond length is 2.18 Å. The Mn(1)-O(3) bond length is 2.23 Å. There are two shorter (2.16 Å) and two longer (2.64 Å) Mn(1)-O(1) bond lengths. In the second Mn site, Mn(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted MnO6 octahedra that share corners with four equivalent Mn(1)O6 pentagonal pyramids, corners with two equivalent P(1)O4 tetrahedra, edges with two equivalent Mn(2)O6 octahedra, edges with two equivalent Mn(1)O6 pentagonal pyramids, and edges with two equivalent P(1)O4 tetrahedra. Both Mn(2)-O(1) bond lengths are 2.43 Å. Both Mn(2)-O(2) bond lengths are 2.35 Å. Both Mn(2)-O(3) bond lengths are 2.42 Å. P(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form PO4 tetrahedra that share corners with two equivalent Mn(2)O6 octahedra, corners with four equivalent Mn(1)O6 pentagonal pyramids, edges with two equivalent Mn(2)O6 octahedra, and  an edgeedge with one Mn(1)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles are 61°. The P(1)-O(2) bond length is 1.59 Å. The P(1)-O(3) bond length is 1.57 Å. Both P(1)-O(1) bond lengths are 1.55 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Mn(2), two equivalent Mn(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Mn(1), two equivalent Mn(2), and one P(1) atom. In the third O site, O(3) is bonded to one Mn(1), two equivalent Mn(2), and one P(1) atom to form distorted corner-sharing OMn3P tetrahedra.