Li2MnSi4O11 crystallizes in the monoclinic C2/c space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a 3-coordinate geometry to one O(6) and two equivalent O(5) atoms. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to two equivalent O(3) and two equivalent O(5) atoms. Mn(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form MnO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra and corners with four equivalent Si(1)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(4) atom to form SiO4 tetrahedra that share corners with two equivalent Mn(1)O6 octahedra and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 24-52°. 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 Mn(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 46°. There are six inequivalent O sites. In the first O site, O(3) is bonded in a trigonal non-coplanar geometry to one Li(2), one Mn(1), and one Si(1) atom. In the second O site, O(4) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the third O site, O(5) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Mn(1), and one Si(2) atom. In the fourth O site, O(6) is bonded in a trigonal planar geometry to one Li(1) and two equivalent Si(2) atoms. In the fifth O site, O(1) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the sixth O site, O(2) is bonded in a bent 150 degrees geometry to one Mn(1) and one Si(1) atom.
Li2MnSi4O11 crystallizes in the monoclinic C2/c space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a 3-coordinate geometry to one O(6) and two equivalent O(5) atoms. The Li(1)-O(6) bond length is 2.05 Å. Both Li(1)-O(5) bond lengths are 2.13 Å. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to two equivalent O(3) and two equivalent O(5) atoms. Both Li(2)-O(3) bond lengths are 2.10 Å. Both Li(2)-O(5) bond lengths are 2.14 Å. Mn(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form MnO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra and corners with four equivalent Si(1)O4 tetrahedra. Both Mn(1)-O(2) bond lengths are 1.87 Å. Both Mn(1)-O(3) bond lengths are 1.97 Å. Both Mn(1)-O(5) bond lengths are 1.98 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(4) atom to form SiO4 tetrahedra that share corners with two equivalent Mn(1)O6 octahedra and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 24-52°. The Si(1)-O(1) bond length is 1.64 Å. The Si(1)-O(2) bond length is 1.61 Å. The Si(1)-O(3) bond length is 1.63 Å. The Si(1)-O(4) bond length is 1.66 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 Mn(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 46°. The Si(2)-O(1) bond length is 1.62 Å. The Si(2)-O(4) bond length is 1.63 Å. The Si(2)-O(5) bond length is 1.63 Å. The Si(2)-O(6) bond length is 1.66 Å. There are six inequivalent O sites. In the first O site, O(3) is bonded in a trigonal non-coplanar geometry to one Li(2), one Mn(1), and one Si(1) atom. In the second O site, O(4) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the third O site, O(5) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Mn(1), and one Si(2) atom. In the fourth O site, O(6) is bonded in a trigonal planar geometry to one Li(1) and two equivalent Si(2) atoms. In the fifth O site, O(1) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the sixth O site, O(2) is bonded in a bent 150 degrees geometry to one Mn(1) and one Si(1) atom.