Li2MnSi4O11 crystallizes in the tetragonal I4/m space group. Li(1) is bonded in a 3-coordinate geometry to one O(2) and two equivalent O(3) atoms. Mn(1) is bonded to one O(1), one O(2), and four equivalent O(3) atoms to form MnO6 octahedra that share corners with two equivalent Mn(1)O6 octahedra and corners with four equivalent Si(1)O4 tetrahedra. The corner-sharing octahedra are not tilted. Si(1) is bonded to one O(3), one O(4), and two equivalent O(5) atoms to form SiO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra and corners with three equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. There are five inequivalent O sites. In the first O site, O(4) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the second O site, O(5) is bonded in a distorted bent 150 degrees geometry to two equivalent Si(1) atoms. In the third O site, O(1) is bonded in a linear geometry to two equivalent Mn(1) atoms. In the fourth O site, O(2) is bonded in an octahedral geometry to four equivalent Li(1) and two equivalent Mn(1) atoms. In the fifth O site, O(3) is bonded in a 3-coordinate geometry to one Li(1), one Mn(1), and one Si(1) atom.
Li2MnSi4O11 crystallizes in the tetragonal I4/m space group. Li(1) is bonded in a 3-coordinate geometry to one O(2) and two equivalent O(3) atoms. The Li(1)-O(2) bond length is 2.02 Å. Both Li(1)-O(3) bond lengths are 2.04 Å. Mn(1) is bonded to one O(1), one O(2), and four equivalent O(3) atoms to form MnO6 octahedra that share corners with two equivalent Mn(1)O6 octahedra and corners with four equivalent Si(1)O4 tetrahedra. The corner-sharing octahedra are not tilted. The Mn(1)-O(1) bond length is 1.90 Å. The Mn(1)-O(2) bond length is 2.00 Å. All Mn(1)-O(3) bond lengths are 1.95 Å. Si(1) is bonded to one O(3), one O(4), and two equivalent O(5) atoms to form SiO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra and corners with three equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. The Si(1)-O(3) bond length is 1.62 Å. The Si(1)-O(4) bond length is 1.63 Å. There is one shorter (1.64 Å) and one longer (1.65 Å) Si(1)-O(5) bond length. There are five inequivalent O sites. In the first O site, O(4) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the second O site, O(5) is bonded in a distorted bent 150 degrees geometry to two equivalent Si(1) atoms. In the third O site, O(1) is bonded in a linear geometry to two equivalent Mn(1) atoms. In the fourth O site, O(2) is bonded in an octahedral geometry to four equivalent Li(1) and two equivalent Mn(1) atoms. In the fifth O site, O(3) is bonded in a 3-coordinate geometry to one Li(1), one Mn(1), and one Si(1) atom.