Li2Mn(SiO3)2 crystallizes in the monoclinic C2 space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(3), one O(5), and two equivalent O(2) atoms to form LiO4 trigonal pyramids that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Mn(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra,  an edgeedge with one Li(2)O4 tetrahedra, and  an edgeedge with one Li(1)O4 trigonal pyramid. In the second Li site, Li(2) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form distorted LiO4 tetrahedra that share corners with two equivalent Mn(1)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Li(1)O4 trigonal pyramids, and edges with two equivalent Li(1)O4 trigonal pyramids. In the third Li site, Li(3) is bonded to two equivalent O(1) and two equivalent O(6) atoms to form distorted LiO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  an edgeedge with one Mn(1)O4 tetrahedra, and edges with two equivalent Mn(2)O4 tetrahedra. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted MnO4 tetrahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Mn(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Li(1)O4 trigonal pyramids, and  an edgeedge with one Li(3)O4 tetrahedra. In the second Mn site, Mn(2) is bonded to two equivalent O(1) and two equivalent O(6) atoms to form distorted MnO4 tetrahedra that share corners with two equivalent Mn(1)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and edges with two equivalent Li(3)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(4), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Li(3)O4 tetrahedra,  a cornercorner with one Mn(1)O4 tetrahedra,  a cornercorner with one Mn(2)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with three equivalent Li(1)O4 trigonal pyramids. In the second Si site, Si(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Li(3)O4 tetrahedra,  a cornercorner with one Mn(1)O4 tetrahedra,  a cornercorner with one Mn(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Li(1)O4 trigonal pyramids. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Li(3), one Mn(1), one Mn(2), and one Si(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Li(2), two equivalent Li(1), and one Si(1) atom. In the third O site, O(3) is bonded to one Li(1), one Li(2), one Mn(1), and one Si(2) atom to form distorted corner-sharing OLi2MnSi tetrahedra. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Li(1), one Si(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Li(3), one Mn(2), and one Si(2) atom.
Li2Mn(SiO3)2 crystallizes in the monoclinic C2 space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(3), one O(5), and two equivalent O(2) atoms to form LiO4 trigonal pyramids that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Mn(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra,  an edgeedge with one Li(2)O4 tetrahedra, and  an edgeedge with one Li(1)O4 trigonal pyramid. The Li(1)-O(3) bond length is 2.04 Å. The Li(1)-O(5) bond length is 2.12 Å. There is one shorter (1.94 Å) and one longer (2.01 Å) Li(1)-O(2) bond length. In the second Li site, Li(2) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form distorted LiO4 tetrahedra that share corners with two equivalent Mn(1)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Li(1)O4 trigonal pyramids, and edges with two equivalent Li(1)O4 trigonal pyramids. Both Li(2)-O(2) bond lengths are 1.98 Å. Both Li(2)-O(3) bond lengths are 1.86 Å. In the third Li site, Li(3) is bonded to two equivalent O(1) and two equivalent O(6) atoms to form distorted LiO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  an edgeedge with one Mn(1)O4 tetrahedra, and edges with two equivalent Mn(2)O4 tetrahedra. Both Li(3)-O(1) bond lengths are 2.02 Å. Both Li(3)-O(6) bond lengths are 1.83 Å. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted MnO4 tetrahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Mn(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Li(1)O4 trigonal pyramids, and  an edgeedge with one Li(3)O4 tetrahedra. Both Mn(1)-O(1) bond lengths are 2.11 Å. Both Mn(1)-O(3) bond lengths are 1.98 Å. In the second Mn site, Mn(2) is bonded to two equivalent O(1) and two equivalent O(6) atoms to form distorted MnO4 tetrahedra that share corners with two equivalent Mn(1)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and edges with two equivalent Li(3)O4 tetrahedra. Both Mn(2)-O(1) bond lengths are 2.07 Å. Both Mn(2)-O(6) 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(4), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Li(3)O4 tetrahedra,  a cornercorner with one Mn(1)O4 tetrahedra,  a cornercorner with one Mn(2)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with three equivalent Li(1)O4 trigonal pyramids. The Si(1)-O(1) bond length is 1.65 Å. The Si(1)-O(2) bond length is 1.60 Å. The Si(1)-O(4) bond length is 1.65 Å. The Si(1)-O(5) bond length is 1.66 Å. In the second Si site, Si(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Li(3)O4 tetrahedra,  a cornercorner with one Mn(1)O4 tetrahedra,  a cornercorner with one Mn(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Li(1)O4 trigonal pyramids. The Si(2)-O(3) bond length is 1.62 Å. The Si(2)-O(4) bond length is 1.64 Å. The Si(2)-O(5) bond length is 1.66 Å. The Si(2)-O(6) bond length is 1.59 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Li(3), one Mn(1), one Mn(2), and one Si(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Li(2), two equivalent Li(1), and one Si(1) atom. In the third O site, O(3) is bonded to one Li(1), one Li(2), one Mn(1), and one Si(2) atom to form distorted corner-sharing OLi2MnSi tetrahedra. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Li(1), one Si(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Li(3), one Mn(2), and one Si(2) atom.