Li2Fe(CO3)2 crystallizes in the monoclinic P2_1/c space group. Li(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form distorted LiO4 trigonal pyramids that share corners with two equivalent Fe(1)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, and  an edgeedge with one Li(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 44-82°. Fe(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted FeO6 octahedra that share corners with four equivalent Li(1)O4 trigonal pyramids and edges with two equivalent Li(1)O4 trigonal pyramids. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1), one Fe(1), and one C(1) atom to form a mixture of distorted corner and edge-sharing OLi2FeC trigonal pyramids. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one C(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Li(1), one Fe(1), and one C(1) atom.
Li2Fe(CO3)2 crystallizes in the monoclinic P2_1/c space group. Li(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form distorted LiO4 trigonal pyramids that share corners with two equivalent Fe(1)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, and  an edgeedge with one Li(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 44-82°. The Li(1)-O(2) bond length is 1.99 Å. The Li(1)-O(3) bond length is 1.95 Å. There is one shorter (1.99 Å) and one longer (2.12 Å) Li(1)-O(1) bond length. Fe(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted FeO6 octahedra that share corners with four equivalent Li(1)O4 trigonal pyramids and edges with two equivalent Li(1)O4 trigonal pyramids. Both Fe(1)-O(1) bond lengths are 2.21 Å. Both Fe(1)-O(2) bond lengths are 2.07 Å. Both Fe(1)-O(3) bond lengths are 2.26 Å. 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 1.31 Å. The C(1)-O(2) bond length is 1.29 Å. The C(1)-O(3) bond length is 1.29 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1), one Fe(1), and one C(1) atom to form a mixture of distorted corner and edge-sharing OLi2FeC trigonal pyramids. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one C(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Li(1), one Fe(1), and one C(1) atom.