Li4Mn2Si3O10 crystallizes in the monoclinic C2/c space group. There are two 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 tetrahedra that share corners with four equivalent Si(1)O4 tetrahedra, corners with three equivalent Mn(1)O5 trigonal bipyramids,  an edgeedge with one Li(1)O4 tetrahedra, and  an edgeedge with one Mn(1)O5 trigonal bipyramid. In the second Li site, Li(2) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(1), and two equivalent O(4) atoms. Mn(1) is bonded to one O(1), one O(2), one O(3), and two equivalent O(5) atoms to form MnO5 trigonal bipyramids that share  a cornercorner with one Si(2)O4 tetrahedra, corners with three equivalent Li(1)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra,  an edgeedge with one Li(1)O4 tetrahedra, and  an edgeedge with one Mn(1)O5 trigonal bipyramid. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra, corners with four equivalent Li(1)O4 tetrahedra, and corners with four equivalent Mn(1)O5 trigonal bipyramids. In the second Si site, Si(2) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form SiO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra and corners with two equivalent Mn(1)O5 trigonal bipyramids. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(2), one Mn(1), and one Si(2) atom to form distorted OLi2MnSi trigonal pyramids that share  a cornercorner with one O(3)Li2MnSi tetrahedra, corners with two equivalent O(5)LiMn2Si tetrahedra, corners with three equivalent O(1)Li2MnSi trigonal pyramids, and  an edgeedge with one O(3)Li2MnSi tetrahedra. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Li(1), one Mn(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(1) atom to form distorted OLi2MnSi tetrahedra that share corners with four equivalent O(5)LiMn2Si tetrahedra,  a cornercorner with one O(1)Li2MnSi trigonal pyramid, and  an edgeedge with one O(1)Li2MnSi trigonal pyramid. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Li(2), one Si(1), and one Si(2) atom. In the fifth O site, O(5) is bonded to one Li(1), two equivalent Mn(1), and one Si(1) atom to form distorted OLiMn2Si tetrahedra that share corners with four equivalent O(3)Li2MnSi tetrahedra, corners with two equivalent O(1)Li2MnSi trigonal pyramids, and  an edgeedge with one O(5)LiMn2Si tetrahedra.
Li4Mn2Si3O10 crystallizes in the monoclinic C2/c space group. There are two 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 tetrahedra that share corners with four equivalent Si(1)O4 tetrahedra, corners with three equivalent Mn(1)O5 trigonal bipyramids,  an edgeedge with one Li(1)O4 tetrahedra, and  an edgeedge with one Mn(1)O5 trigonal bipyramid. The Li(1)-O(3) bond length is 1.98 Å. The Li(1)-O(5) bond length is 2.05 Å. There is one shorter (1.91 Å) and one longer (2.00 Å) Li(1)-O(2) bond length. In the second Li site, Li(2) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(1), and two equivalent O(4) atoms. The Li(2)-O(3) bond length is 2.09 Å. There is one shorter (2.03 Å) and one longer (2.07 Å) Li(2)-O(1) bond length. There is one shorter (2.37 Å) and one longer (2.55 Å) Li(2)-O(4) bond length. Mn(1) is bonded to one O(1), one O(2), one O(3), and two equivalent O(5) atoms to form MnO5 trigonal bipyramids that share  a cornercorner with one Si(2)O4 tetrahedra, corners with three equivalent Li(1)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra,  an edgeedge with one Li(1)O4 tetrahedra, and  an edgeedge with one Mn(1)O5 trigonal bipyramid. The Mn(1)-O(1) bond length is 2.22 Å. The Mn(1)-O(2) bond length is 2.16 Å. The Mn(1)-O(3) bond length is 2.13 Å. There is one shorter (2.12 Å) and one longer (2.26 Å) Mn(1)-O(5) bond length. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra, corners with four equivalent Li(1)O4 tetrahedra, and corners with four equivalent Mn(1)O5 trigonal bipyramids. The Si(1)-O(2) bond length is 1.63 Å. The Si(1)-O(3) bond length is 1.64 Å. The Si(1)-O(4) bond length is 1.68 Å. The Si(1)-O(5) bond length is 1.64 Å. In the second Si site, Si(2) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form SiO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra and corners with two equivalent Mn(1)O5 trigonal bipyramids. Both Si(2)-O(1) bond lengths are 1.62 Å. Both Si(2)-O(4) bond lengths are 1.67 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(2), one Mn(1), and one Si(2) atom to form distorted OLi2MnSi trigonal pyramids that share  a cornercorner with one O(3)Li2MnSi tetrahedra, corners with two equivalent O(5)LiMn2Si tetrahedra, corners with three equivalent O(1)Li2MnSi trigonal pyramids, and  an edgeedge with one O(3)Li2MnSi tetrahedra. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Li(1), one Mn(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(1) atom to form distorted OLi2MnSi tetrahedra that share corners with four equivalent O(5)LiMn2Si tetrahedra,  a cornercorner with one O(1)Li2MnSi trigonal pyramid, and  an edgeedge with one O(1)Li2MnSi trigonal pyramid. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Li(2), one Si(1), and one Si(2) atom. In the fifth O site, O(5) is bonded to one Li(1), two equivalent Mn(1), and one Si(1) atom to form distorted OLiMn2Si tetrahedra that share corners with four equivalent O(3)Li2MnSi tetrahedra, corners with two equivalent O(1)Li2MnSi trigonal pyramids, and  an edgeedge with one O(5)LiMn2Si tetrahedra.