Li2Mn2Si2O7 is Chalcostibite-derived structured and crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a distorted trigonal non-coplanar geometry to one O(4), one O(5), and one O(7) atom. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(2), one O(4), one O(5), and one O(6) atom. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(6), one O(7), and two equivalent O(3) atoms. In the second Mn site, Mn(2) is bonded to one O(3), one O(4), one O(5), and one O(7) atom to form MnO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra and corners with two equivalent Si(2)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra and corners with two equivalent Mn(2)O4 tetrahedra. In the second Si site, Si(2) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra and corners with two equivalent Mn(2)O4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Mn(1), one Si(1), and one Si(2) atom. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Li(2), one Mn(1), and one Si(1) atom. In the third O site, O(3) is bonded to one Mn(2), two equivalent Mn(1), and one Si(1) atom to form distorted OMn3Si tetrahedra that share  a cornercorner with one O(4)Li2MnSi tetrahedra,  a cornercorner with one O(5)Li2MnSi tetrahedra, corners with two equivalent O(7)LiMn2Si tetrahedra,  an edgeedge with one O(7)LiMn2Si tetrahedra, and  an edgeedge with one O(3)Mn3Si tetrahedra. In the fourth O site, O(4) is bonded to one Li(1), one Li(2), one Mn(2), and one Si(2) atom to form distorted OLi2MnSi tetrahedra that share  a cornercorner with one O(3)Mn3Si tetrahedra, corners with two equivalent O(7)LiMn2Si tetrahedra, and corners with four equivalent O(5)Li2MnSi tetrahedra. In the fifth O site, O(5) is bonded to one Li(1), one Li(2), one Mn(2), and one Si(2) atom to form OLi2MnSi tetrahedra that share  a cornercorner with one O(3)Mn3Si tetrahedra, corners with two equivalent O(7)LiMn2Si tetrahedra, and corners with four equivalent O(4)Li2MnSi tetrahedra. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Li(2), one Mn(1), and one Si(2) atom. In the seventh O site, O(7) is bonded to one Li(1), one Mn(1), one Mn(2), and one Si(1) atom to form distorted OLiMn2Si tetrahedra that share corners with two equivalent O(4)Li2MnSi tetrahedra, corners with two equivalent O(5)Li2MnSi tetrahedra, corners with two equivalent O(3)Mn3Si tetrahedra, and  an edgeedge with one O(3)Mn3Si tetrahedra.
Li2Mn2Si2O7 is Chalcostibite-derived structured and crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a distorted trigonal non-coplanar geometry to one O(4), one O(5), and one O(7) atom. The Li(1)-O(4) bond length is 2.17 Å. The Li(1)-O(5) bond length is 1.99 Å. The Li(1)-O(7) bond length is 2.01 Å. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(2), one O(4), one O(5), and one O(6) atom. The Li(2)-O(2) bond length is 1.99 Å. The Li(2)-O(4) bond length is 2.22 Å. The Li(2)-O(5) bond length is 2.36 Å. The Li(2)-O(6) bond length is 2.09 Å. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(6), one O(7), and two equivalent O(3) atoms. The Mn(1)-O(1) bond length is 2.52 Å. The Mn(1)-O(2) bond length is 2.08 Å. The Mn(1)-O(6) bond length is 2.05 Å. The Mn(1)-O(7) bond length is 2.32 Å. There is one shorter (2.19 Å) and one longer (2.38 Å) Mn(1)-O(3) bond length. In the second Mn site, Mn(2) is bonded to one O(3), one O(4), one O(5), and one O(7) atom to form MnO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra and corners with two equivalent Si(2)O4 tetrahedra. The Mn(2)-O(3) bond length is 2.10 Å. The Mn(2)-O(4) bond length is 2.08 Å. The Mn(2)-O(5) bond length is 2.07 Å. The Mn(2)-O(7) bond length is 2.12 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra and corners with two equivalent Mn(2)O4 tetrahedra. The Si(1)-O(1) bond length is 1.67 Å. The Si(1)-O(2) bond length is 1.62 Å. The Si(1)-O(3) bond length is 1.66 Å. The Si(1)-O(7) bond length is 1.65 Å. In the second Si site, Si(2) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra and corners with two equivalent Mn(2)O4 tetrahedra. The Si(2)-O(1) bond length is 1.69 Å. The Si(2)-O(4) bond length is 1.66 Å. The Si(2)-O(5) bond length is 1.65 Å. The Si(2)-O(6) bond length is 1.63 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Mn(1), one Si(1), and one Si(2) atom. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Li(2), one Mn(1), and one Si(1) atom. In the third O site, O(3) is bonded to one Mn(2), two equivalent Mn(1), and one Si(1) atom to form distorted OMn3Si tetrahedra that share  a cornercorner with one O(4)Li2MnSi tetrahedra,  a cornercorner with one O(5)Li2MnSi tetrahedra, corners with two equivalent O(7)LiMn2Si tetrahedra,  an edgeedge with one O(7)LiMn2Si tetrahedra, and  an edgeedge with one O(3)Mn3Si tetrahedra. In the fourth O site, O(4) is bonded to one Li(1), one Li(2), one Mn(2), and one Si(2) atom to form distorted OLi2MnSi tetrahedra that share  a cornercorner with one O(3)Mn3Si tetrahedra, corners with two equivalent O(7)LiMn2Si tetrahedra, and corners with four equivalent O(5)Li2MnSi tetrahedra. In the fifth O site, O(5) is bonded to one Li(1), one Li(2), one Mn(2), and one Si(2) atom to form OLi2MnSi tetrahedra that share  a cornercorner with one O(3)Mn3Si tetrahedra, corners with two equivalent O(7)LiMn2Si tetrahedra, and corners with four equivalent O(4)Li2MnSi tetrahedra. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Li(2), one Mn(1), and one Si(2) atom. In the seventh O site, O(7) is bonded to one Li(1), one Mn(1), one Mn(2), and one Si(1) atom to form distorted OLiMn2Si tetrahedra that share corners with two equivalent O(4)Li2MnSi tetrahedra, corners with two equivalent O(5)Li2MnSi tetrahedra, corners with two equivalent O(3)Mn3Si tetrahedra, and  an edgeedge with one O(3)Mn3Si tetrahedra.