LiFeSiO4 crystallizes in the monoclinic P2_1/c space group. Li(1) is bonded in a distorted square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. Fe(1) is bonded to one O(1), one O(2), one O(3), and two equivalent O(4) atoms to form FeO5 trigonal bipyramids that share corners with three equivalent Si(1)O4 tetrahedra,  an edgeedge with one Si(1)O4 tetrahedra, and  an edgeedge with one Fe(1)O5 trigonal bipyramid. 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 corners with three equivalent Fe(1)O5 trigonal bipyramids and  an edgeedge with one Fe(1)O5 trigonal bipyramid. There are four 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 corner-sharing OLi2FeSi tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Li(1), one Fe(1), and one Si(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Fe(1) and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Fe(1) and one Si(1) atom.
LiFeSiO4 crystallizes in the monoclinic P2_1/c space group. Li(1) is bonded in a distorted square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. There is one shorter (2.01 Å) and one longer (2.02 Å) Li(1)-O(1) bond length. There is one shorter (2.06 Å) and one longer (2.53 Å) Li(1)-O(2) bond length. Fe(1) is bonded to one O(1), one O(2), one O(3), and two equivalent O(4) atoms to form FeO5 trigonal bipyramids that share corners with three equivalent Si(1)O4 tetrahedra,  an edgeedge with one Si(1)O4 tetrahedra, and  an edgeedge with one Fe(1)O5 trigonal bipyramid. The Fe(1)-O(1) bond length is 2.00 Å. The Fe(1)-O(2) bond length is 2.00 Å. The Fe(1)-O(3) bond length is 1.90 Å. There is one shorter (1.98 Å) and one longer (2.13 Å) Fe(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 corners with three equivalent Fe(1)O5 trigonal bipyramids and  an edgeedge with one Fe(1)O5 trigonal bipyramid. The Si(1)-O(1) bond length is 1.68 Å. The Si(1)-O(2) bond length is 1.66 Å. The Si(1)-O(3) bond length is 1.63 Å. The Si(1)-O(4) bond length is 1.67 Å. There are four 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 corner-sharing OLi2FeSi tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Li(1), one Fe(1), and one Si(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Fe(1) and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Fe(1) and one Si(1) atom.