Li2FeCO4 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(4), and two equivalent O(1) atoms to form a mixture of corner and edge-sharing LiO4 tetrahedra. In the second Li site, Li(2) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form a mixture of corner and edge-sharing LiO4 tetrahedra. Fe(1) is bonded in a trigonal planar geometry to one O(3) and two equivalent O(4) atoms. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Li(2), two equivalent Li(1), and one C(1) atom to form distorted OLi3C tetrahedra that share  a cornercorner with one O(4)Li2Fe2 tetrahedra, corners with two equivalent O(1)Li3C tetrahedra, and  an edgeedge with one O(4)Li2Fe2 tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(2), and one C(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Li(2), one Fe(1), and one C(1) atom. In the fourth O site, O(4) is bonded to one Li(1), one Li(2), and two equivalent Fe(1) atoms to form OLi2Fe2 tetrahedra that share  a cornercorner with one O(1)Li3C tetrahedra, corners with two equivalent O(4)Li2Fe2 tetrahedra, and  an edgeedge with one O(1)Li3C tetrahedra.
Li2FeCO4 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(4), and two equivalent O(1) atoms to form a mixture of corner and edge-sharing LiO4 tetrahedra. The Li(1)-O(2) bond length is 1.93 Å. The Li(1)-O(4) bond length is 1.90 Å. There is one shorter (1.96 Å) and one longer (1.97 Å) Li(1)-O(1) bond length. In the second Li site, Li(2) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form a mixture of corner and edge-sharing LiO4 tetrahedra. The Li(2)-O(1) bond length is 2.04 Å. The Li(2)-O(2) bond length is 1.91 Å. The Li(2)-O(3) bond length is 1.94 Å. The Li(2)-O(4) bond length is 1.89 Å. Fe(1) is bonded in a trigonal planar geometry to one O(3) and two equivalent O(4) atoms. The Fe(1)-O(3) bond length is 1.97 Å. There is one shorter (1.86 Å) and one longer (1.87 Å) Fe(1)-O(4) bond length. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The C(1)-O(1) bond length is 1.29 Å. The C(1)-O(2) bond length is 1.27 Å. The C(1)-O(3) bond length is 1.31 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Li(2), two equivalent Li(1), and one C(1) atom to form distorted OLi3C tetrahedra that share  a cornercorner with one O(4)Li2Fe2 tetrahedra, corners with two equivalent O(1)Li3C tetrahedra, and  an edgeedge with one O(4)Li2Fe2 tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(2), and one C(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Li(2), one Fe(1), and one C(1) atom. In the fourth O site, O(4) is bonded to one Li(1), one Li(2), and two equivalent Fe(1) atoms to form OLi2Fe2 tetrahedra that share  a cornercorner with one O(1)Li3C tetrahedra, corners with two equivalent O(4)Li2Fe2 tetrahedra, and  an edgeedge with one O(1)Li3C tetrahedra.