LiFeSiO4 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a distorted trigonal planar geometry to one O(1), one O(2), and one O(3) atom. In the second Li site, Li(2) is bonded in a distorted T-shaped geometry to one O(6), one O(7), and one O(8) atom. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form FeO5 trigonal bipyramids that share  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  a cornercorner with one Fe(2)O5 trigonal bipyramid, and  an edgeedge with one Si(1)O4 tetrahedra. In the second Fe site, Fe(2) is bonded to one O(1), one O(4), one O(8), and two equivalent O(5) atoms to form FeO5 trigonal bipyramids that share  a cornercorner with one Si(1)O4 tetrahedra, corners with four equivalent Si(2)O4 tetrahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid, and  an edgeedge with one Fe(2)O5 trigonal bipyramid. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O5 trigonal bipyramid,  a cornercorner with one Fe(2)O5 trigonal bipyramid, and  an edgeedge with one Fe(1)O5 trigonal bipyramid. In the second Si site, Si(2) is bonded to one O(1), one O(4), one O(5), and one O(7) atom to form SiO4 tetrahedra that share corners with two equivalent Fe(1)O5 trigonal bipyramids and corners with four equivalent Fe(2)O5 trigonal bipyramids. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Li(1), one Fe(2), and one Si(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one Si(1) atom. In the third O site, O(3) is bonded in a T-shaped geometry to one Li(1), one Fe(1), and one Si(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Fe(1), one Fe(2), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to two equivalent Fe(2) and one Si(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one Si(1) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Li(2), one Fe(1), and one Si(2) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Li(2), one Fe(2), and one Si(1) atom.
LiFeSiO4 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a distorted trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The Li(1)-O(1) bond length is 1.97 Å. The Li(1)-O(2) bond length is 1.92 Å. The Li(1)-O(3) bond length is 1.89 Å. In the second Li site, Li(2) is bonded in a distorted T-shaped geometry to one O(6), one O(7), and one O(8) atom. The Li(2)-O(6) bond length is 1.97 Å. The Li(2)-O(7) bond length is 1.88 Å. The Li(2)-O(8) bond length is 1.94 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form FeO5 trigonal bipyramids that share  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  a cornercorner with one Fe(2)O5 trigonal bipyramid, and  an edgeedge with one Si(1)O4 tetrahedra. The Fe(1)-O(2) bond length is 2.00 Å. The Fe(1)-O(3) bond length is 2.01 Å. The Fe(1)-O(4) bond length is 2.06 Å. The Fe(1)-O(6) bond length is 1.96 Å. The Fe(1)-O(7) bond length is 1.99 Å. In the second Fe site, Fe(2) is bonded to one O(1), one O(4), one O(8), and two equivalent O(5) atoms to form FeO5 trigonal bipyramids that share  a cornercorner with one Si(1)O4 tetrahedra, corners with four equivalent Si(2)O4 tetrahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid, and  an edgeedge with one Fe(2)O5 trigonal bipyramid. The Fe(2)-O(1) bond length is 1.90 Å. The Fe(2)-O(4) bond length is 2.05 Å. The Fe(2)-O(8) bond length is 1.95 Å. There is one shorter (1.99 Å) and one longer (2.07 Å) Fe(2)-O(5) bond length. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O5 trigonal bipyramid,  a cornercorner with one Fe(2)O5 trigonal bipyramid, and  an edgeedge with one Fe(1)O5 trigonal bipyramid. The Si(1)-O(2) bond length is 1.66 Å. The Si(1)-O(3) bond length is 1.65 Å. The Si(1)-O(6) bond length is 1.64 Å. The Si(1)-O(8) bond length is 1.66 Å. In the second Si site, Si(2) is bonded to one O(1), one O(4), one O(5), and one O(7) atom to form SiO4 tetrahedra that share corners with two equivalent Fe(1)O5 trigonal bipyramids and corners with four equivalent Fe(2)O5 trigonal bipyramids. The Si(2)-O(1) bond length is 1.64 Å. The Si(2)-O(4) bond length is 1.66 Å. The Si(2)-O(5) bond length is 1.67 Å. The Si(2)-O(7) bond length is 1.63 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Li(1), one Fe(2), and one Si(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one Si(1) atom. In the third O site, O(3) is bonded in a T-shaped geometry to one Li(1), one Fe(1), and one Si(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Fe(1), one Fe(2), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to two equivalent Fe(2) and one Si(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one Si(1) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Li(2), one Fe(1), and one Si(2) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Li(2), one Fe(2), and one Si(1) atom.