MnPO4 crystallizes in the monoclinic P2_1/c space group. Mn(1) is bonded to one O(1), one O(2), one O(4), and two equivalent O(3) atoms to form distorted MnO5 square pyramids that share corners with three equivalent P(1)O4 tetrahedra,  an edgeedge with one Mn(1)O5 square pyramid, 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 three equivalent Mn(1)O5 square pyramids and  an edgeedge with one Mn(1)O5 square pyramid. There are four inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Mn(1) and one P(1) atom. In the second O site, O(2) is bonded in an L-shaped geometry to one Mn(1) and one P(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to two equivalent Mn(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Mn(1) and one P(1) atom.
MnPO4 crystallizes in the monoclinic P2_1/c space group. Mn(1) is bonded to one O(1), one O(2), one O(4), and two equivalent O(3) atoms to form distorted MnO5 square pyramids that share corners with three equivalent P(1)O4 tetrahedra,  an edgeedge with one Mn(1)O5 square pyramid, and  an edgeedge with one P(1)O4 tetrahedra. The Mn(1)-O(1) bond length is 1.98 Å. The Mn(1)-O(2) bond length is 1.96 Å. The Mn(1)-O(4) bond length is 1.91 Å. There is one shorter (2.03 Å) and one longer (2.19 Å) Mn(1)-O(3) 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 three equivalent Mn(1)O5 square pyramids and  an edgeedge with one Mn(1)O5 square pyramid. The P(1)-O(1) bond length is 1.53 Å. The P(1)-O(2) bond length is 1.56 Å. The P(1)-O(3) bond length is 1.61 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 bent 120 degrees geometry to one Mn(1) and one P(1) atom. In the second O site, O(2) is bonded in an L-shaped geometry to one Mn(1) and one P(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to two equivalent Mn(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Mn(1) and one P(1) atom.