Li2MnP2O7 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(3), one O(4), one O(5), and one O(7) atom to form distorted LiO4 trigonal pyramids that share corners with four equivalent Mn(1)O6 octahedra,  a cornercorner with one Li(2)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 58-74°. In the second Li site, Li(2) is bonded to one O(1), one O(4), and two equivalent O(6) atoms to form distorted LiO4 tetrahedra that share corners with two equivalent Mn(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra,  a cornercorner with one Li(1)O4 trigonal pyramid,  an edgeedge with one Mn(1)O6 octahedra, and  an edgeedge with one Li(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 66-78°. Mn(1) is bonded to one O(1), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form distorted MnO6 octahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, corners with four equivalent Li(1)O4 trigonal pyramids, and  an edgeedge with one Li(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Mn(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent Li(2)O4 tetrahedra, and corners with two equivalent Li(1)O4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 33-63°. In the second P site, P(2) is bonded to one O(1), one O(2), one O(3), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Mn(1)O6 octahedra,  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra, and corners with two equivalent Li(1)O4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 52-59°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Li(2), one Mn(1), and one P(2) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Li(1), one Mn(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a distorted tetrahedral geometry to one Li(1), one Li(2), one Mn(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Li(1), one Mn(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Li(2), one Mn(1), and one P(1) atom. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Li(1), one Mn(1), and one P(2) atom.
Li2MnP2O7 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(3), one O(4), one O(5), and one O(7) atom to form distorted LiO4 trigonal pyramids that share corners with four equivalent Mn(1)O6 octahedra,  a cornercorner with one Li(2)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 58-74°. The Li(1)-O(3) bond length is 2.07 Å. The Li(1)-O(4) bond length is 2.33 Å. The Li(1)-O(5) bond length is 2.05 Å. The Li(1)-O(7) bond length is 2.06 Å. In the second Li site, Li(2) is bonded to one O(1), one O(4), and two equivalent O(6) atoms to form distorted LiO4 tetrahedra that share corners with two equivalent Mn(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra,  a cornercorner with one Li(1)O4 trigonal pyramid,  an edgeedge with one Mn(1)O6 octahedra, and  an edgeedge with one Li(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 66-78°. The Li(2)-O(1) bond length is 1.92 Å. The Li(2)-O(4) bond length is 2.01 Å. There is one shorter (2.00 Å) and one longer (2.08 Å) Li(2)-O(6) bond length. Mn(1) is bonded to one O(1), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form distorted MnO6 octahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, corners with four equivalent Li(1)O4 trigonal pyramids, and  an edgeedge with one Li(2)O4 tetrahedra. The Mn(1)-O(1) bond length is 2.20 Å. The Mn(1)-O(3) bond length is 2.18 Å. The Mn(1)-O(4) bond length is 2.29 Å. The Mn(1)-O(5) bond length is 2.58 Å. The Mn(1)-O(6) bond length is 2.23 Å. The Mn(1)-O(7) bond length is 2.14 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Mn(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent Li(2)O4 tetrahedra, and corners with two equivalent Li(1)O4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 33-63°. The P(1)-O(2) bond length is 1.62 Å. The P(1)-O(4) bond length is 1.54 Å. The P(1)-O(5) bond length is 1.53 Å. The P(1)-O(6) bond length is 1.54 Å. In the second P site, P(2) is bonded to one O(1), one O(2), one O(3), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Mn(1)O6 octahedra,  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra, and corners with two equivalent Li(1)O4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 52-59°. The P(2)-O(1) bond length is 1.53 Å. The P(2)-O(2) bond length is 1.63 Å. The P(2)-O(3) bond length is 1.54 Å. The P(2)-O(7) bond length is 1.54 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Li(2), one Mn(1), and one P(2) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Li(1), one Mn(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a distorted tetrahedral geometry to one Li(1), one Li(2), one Mn(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Li(1), one Mn(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Li(2), one Mn(1), and one P(1) atom. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Li(1), one Mn(1), and one P(2) atom.