Li2MnP2O7 crystallizes in the tetragonal P-42_1m space group. Li(1) is bonded in a 3-coordinate geometry to one O(2) and two equivalent O(3) atoms. Mn(1) is bonded to four equivalent O(3) atoms to form MnO4 tetrahedra that share corners with four equivalent P(1)O4 tetrahedra. P(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra and corners with two equivalent Mn(1)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent P(1) atoms. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Li(1) and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Li(1), one Mn(1), and one P(1) atom.
Li2MnP2O7 crystallizes in the tetragonal P-42_1m space group. Li(1) is bonded in a 3-coordinate geometry to one O(2) and two equivalent O(3) atoms. The Li(1)-O(2) bond length is 1.91 Å. Both Li(1)-O(3) bond lengths are 2.16 Å. Mn(1) is bonded to four equivalent O(3) atoms to form MnO4 tetrahedra that share corners with four equivalent P(1)O4 tetrahedra. All Mn(1)-O(3) bond lengths are 2.10 Å. P(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra and corners with two equivalent Mn(1)O4 tetrahedra. The P(1)-O(1) bond length is 1.62 Å. The P(1)-O(2) bond length is 1.51 Å. Both P(1)-O(3) bond lengths are 1.55 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent P(1) atoms. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Li(1) and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Li(1), one Mn(1), and one P(1) atom.