MgFe6Ge6 crystallizes in the hexagonal P6/mmm space group. Mg(1) is bonded to twelve equivalent Fe(1), two equivalent Ge(1), and six equivalent Ge(2) atoms to form distorted face-sharing MgFe12Ge8 hexagonal bipyramids. Fe(1) is bonded in a 12-coordinate geometry to two equivalent Mg(1), four equivalent Fe(1), two equivalent Ge(1), two equivalent Ge(2), and two equivalent Ge(3) atoms. There are three inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 8-coordinate geometry to one Mg(1), six equivalent Fe(1), and one Ge(1) atom. In the second Ge site, Ge(2) is bonded in a 9-coordinate geometry to three equivalent Mg(1) and six equivalent Fe(1) atoms. In the third Ge site, Ge(3) is bonded in a 6-coordinate geometry to six equivalent Fe(1) atoms.
MgFe6Ge6 crystallizes in the hexagonal P6/mmm space group. Mg(1) is bonded to twelve equivalent Fe(1), two equivalent Ge(1), and six equivalent Ge(2) atoms to form distorted face-sharing MgFe12Ge8 hexagonal bipyramids. All Mg(1)-Fe(1) bond lengths are 3.24 Å. Both Mg(1)-Ge(1) bond lengths are 2.80 Å. All Mg(1)-Ge(2) bond lengths are 2.91 Å. Fe(1) is bonded in a 12-coordinate geometry to two equivalent Mg(1), four equivalent Fe(1), two equivalent Ge(1), two equivalent Ge(2), and two equivalent Ge(3) atoms. All Fe(1)-Fe(1) bond lengths are 2.52 Å. Both Fe(1)-Ge(1) bond lengths are 2.64 Å. Both Fe(1)-Ge(2) bond lengths are 2.51 Å. Both Fe(1)-Ge(3) bond lengths are 2.52 Å. There are three inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 8-coordinate geometry to one Mg(1), six equivalent Fe(1), and one Ge(1) atom. The Ge(1)-Ge(1) bond length is 2.58 Å. In the second Ge site, Ge(2) is bonded in a 9-coordinate geometry to three equivalent Mg(1) and six equivalent Fe(1) atoms. In the third Ge site, Ge(3) is bonded in a 6-coordinate geometry to six equivalent Fe(1) atoms.