Li2Mn2Si2O7 crystallizes in the orthorhombic Ama2 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(3) atoms. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(3) atoms. Mn(1) is bonded to one O(1), one O(3), and two equivalent O(4) atoms to form MnO4 trigonal pyramids that share corners with four equivalent Si(1)O4 tetrahedra and corners with two equivalent Mn(1)O4 trigonal pyramids. 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  a cornercorner with one Si(1)O4 tetrahedra and corners with four equivalent Mn(1)O4 trigonal pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), one Li(2), one Mn(1), and one Si(1) atom to form a mixture of distorted edge and corner-sharing OLi2MnSi tetrahedra. In the second O site, O(2) is bonded in a bent 120 degrees geometry to two equivalent Si(1) atoms. 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 a mixture of distorted edge and corner-sharing OLi2MnSi trigonal pyramids. In the fourth O site, O(4) is bonded in a trigonal planar geometry to two equivalent Mn(1) and one Si(1) atom.
Li2Mn2Si2O7 crystallizes in the orthorhombic Ama2 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(3) atoms. Both Li(1)-O(1) bond lengths are 2.19 Å. Both Li(1)-O(3) bond lengths are 2.37 Å. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(3) atoms. Both Li(2)-O(1) bond lengths are 2.33 Å. Both Li(2)-O(3) bond lengths are 2.12 Å. Mn(1) is bonded to one O(1), one O(3), and two equivalent O(4) atoms to form MnO4 trigonal pyramids that share corners with four equivalent Si(1)O4 tetrahedra and corners with two equivalent Mn(1)O4 trigonal pyramids. The Mn(1)-O(1) bond length is 2.07 Å. The Mn(1)-O(3) bond length is 2.05 Å. There is one shorter (2.07 Å) and one longer (2.08 Å) Mn(1)-O(4) bond length. 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  a cornercorner with one Si(1)O4 tetrahedra and corners with four equivalent Mn(1)O4 trigonal pyramids. The Si(1)-O(1) bond length is 1.64 Å. The Si(1)-O(2) bond length is 1.69 Å. The Si(1)-O(3) bond length is 1.65 Å. The Si(1)-O(4) bond length is 1.65 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), one Li(2), one Mn(1), and one Si(1) atom to form a mixture of distorted edge and corner-sharing OLi2MnSi tetrahedra. In the second O site, O(2) is bonded in a bent 120 degrees geometry to two equivalent Si(1) atoms. 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 a mixture of distorted edge and corner-sharing OLi2MnSi trigonal pyramids. In the fourth O site, O(4) is bonded in a trigonal planar geometry to two equivalent Mn(1) and one Si(1) atom.