Fe7C3 crystallizes in the hexagonal P6_3mc space group. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a distorted L-shaped geometry to two equivalent C(1) atoms. In the second Fe site, Fe(2) is bonded in a 3-coordinate geometry to three equivalent C(1) atoms. In the third Fe site, Fe(3) is bonded in a 3-coordinate geometry to three equivalent C(1) atoms. C(1) is bonded in a 6-coordinate geometry to one Fe(3), two equivalent Fe(1), and three equivalent Fe(2) atoms.
Fe7C3 crystallizes in the hexagonal P6_3mc space group. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a distorted L-shaped geometry to two equivalent C(1) atoms. Both Fe(1)-C(1) bond lengths are 2.04 Å. In the second Fe site, Fe(2) is bonded in a 3-coordinate geometry to three equivalent C(1) atoms. There is one shorter (1.93 Å) and two longer (2.00 Å) Fe(2)-C(1) bond lengths. In the third Fe site, Fe(3) is bonded in a 3-coordinate geometry to three equivalent C(1) atoms. All Fe(3)-C(1) bond lengths are 1.98 Å. C(1) is bonded in a 6-coordinate geometry to one Fe(3), two equivalent Fe(1), and three equivalent Fe(2) atoms.