Li2Si2O5 crystallizes in the orthorhombic Pbcn space group. Li(1) is bonded to one O(3) and three equivalent O(2) atoms to form LiO4 tetrahedra that share corners with four equivalent Li(1)O4 tetrahedra, corners with five equivalent Si(1)O4 tetrahedra, and  an edgeedge with one Li(1)O4 tetrahedra. Si(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form SiO4 tetrahedra that share corners with three equivalent Si(1)O4 tetrahedra and corners with five equivalent Li(1)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the second O site, O(2) is bonded to three equivalent Li(1) and one Si(1) atom to form a mixture of distorted corner and edge-sharing OLi3Si tetrahedra. In the third O site, O(3) is bonded in a trigonal planar geometry to one Li(1) and two equivalent Si(1) atoms.
Li2Si2O5 crystallizes in the orthorhombic Pbcn space group. Li(1) is bonded to one O(3) and three equivalent O(2) atoms to form LiO4 tetrahedra that share corners with four equivalent Li(1)O4 tetrahedra, corners with five equivalent Si(1)O4 tetrahedra, and  an edgeedge with one Li(1)O4 tetrahedra. The Li(1)-O(3) bond length is 2.05 Å. There are a spread of Li(1)-O(2) bond distances ranging from 1.91-2.00 Å. Si(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form SiO4 tetrahedra that share corners with three equivalent Si(1)O4 tetrahedra and corners with five equivalent Li(1)O4 tetrahedra. The Si(1)-O(1) bond length is 1.61 Å. The Si(1)-O(2) bond length is 1.59 Å. There is one shorter (1.65 Å) and one longer (1.66 Å) Si(1)-O(3) bond length. There are three inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the second O site, O(2) is bonded to three equivalent Li(1) and one Si(1) atom to form a mixture of distorted corner and edge-sharing OLi3Si tetrahedra. In the third O site, O(3) is bonded in a trigonal planar geometry to one Li(1) and two equivalent Si(1) atoms.