Li2MnSiO4 is beta beryllia-derived structured and crystallizes in the orthorhombic Pnma space group. Li(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form LiO4 tetrahedra that share corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, corners with two equivalent Mn(1)O4 trigonal pyramids, and  an edgeedge with one Mn(1)O4 trigonal pyramid. Mn(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form MnO4 trigonal pyramids that share corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, and edges with two equivalent Li(1)O4 tetrahedra. Si(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with eight equivalent Li(1)O4 tetrahedra and corners with four equivalent Mn(1)O4 trigonal pyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1), one Mn(1), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OLi2MnSi tetrahedra. In the second O site, O(2) is bonded to two equivalent Li(1), one Mn(1), and one Si(1) atom to form corner-sharing OLi2MnSi tetrahedra. In the third O site, O(3) is bonded to two equivalent Li(1), one Mn(1), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OLi2MnSi trigonal pyramids.
Li2MnSiO4 is beta beryllia-derived structured and crystallizes in the orthorhombic Pnma space group. Li(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form LiO4 tetrahedra that share corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, corners with two equivalent Mn(1)O4 trigonal pyramids, and  an edgeedge with one Mn(1)O4 trigonal pyramid. The Li(1)-O(2) bond length is 1.95 Å. The Li(1)-O(3) bond length is 2.03 Å. There is one shorter (1.94 Å) and one longer (2.05 Å) Li(1)-O(1) bond length. Mn(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form MnO4 trigonal pyramids that share corners with four equivalent Li(1)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, and edges with two equivalent Li(1)O4 tetrahedra. The Mn(1)-O(2) bond length is 2.07 Å. The Mn(1)-O(3) bond length is 2.17 Å. Both Mn(1)-O(1) bond lengths are 2.07 Å. Si(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with eight equivalent Li(1)O4 tetrahedra and corners with four equivalent Mn(1)O4 trigonal pyramids. The Si(1)-O(2) bond length is 1.66 Å. The Si(1)-O(3) bond length is 1.66 Å. Both Si(1)-O(1) bond lengths are 1.65 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1), one Mn(1), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OLi2MnSi tetrahedra. In the second O site, O(2) is bonded to two equivalent Li(1), one Mn(1), and one Si(1) atom to form corner-sharing OLi2MnSi tetrahedra. In the third O site, O(3) is bonded to two equivalent Li(1), one Mn(1), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OLi2MnSi trigonal pyramids.