Li2FeSiO4 crystallizes in the trigonal P3_121 space group. Li(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form LiO4 tetrahedra that share corners with four equivalent Li(1)O4 tetrahedra and corners with four equivalent Si(1)O4 tetrahedra. Fe(1) is bonded in a distorted square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. Si(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with eight equivalent Li(1)O4 tetrahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1), one Fe(1), and one Si(1) atom to form a mixture of distorted edge and corner-sharing OLi2FeSi tetrahedra. In the second O site, O(2) is bonded to two equivalent Li(1), one Fe(1), and one Si(1) atom to form a mixture of distorted edge and corner-sharing OLi2FeSi tetrahedra.
Li2FeSiO4 crystallizes in the trigonal P3_121 space group. Li(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form LiO4 tetrahedra that share corners with four equivalent Li(1)O4 tetrahedra and corners with four equivalent Si(1)O4 tetrahedra. There is one shorter (1.99 Å) and one longer (2.07 Å) Li(1)-O(1) bond length. There is one shorter (1.95 Å) and one longer (2.00 Å) Li(1)-O(2) bond length. Fe(1) is bonded in a distorted square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. Both Fe(1)-O(1) bond lengths are 2.03 Å. Both Fe(1)-O(2) bond lengths are 2.08 Å. Si(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with eight equivalent Li(1)O4 tetrahedra. Both Si(1)-O(1) bond lengths are 1.65 Å. Both Si(1)-O(2) bond lengths are 1.65 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1), one Fe(1), and one Si(1) atom to form a mixture of distorted edge and corner-sharing OLi2FeSi tetrahedra. In the second O site, O(2) is bonded to two equivalent Li(1), one Fe(1), and one Si(1) atom to form a mixture of distorted edge and corner-sharing OLi2FeSi tetrahedra.