Fe7Ge4 crystallizes in the hexagonal P6_3/mmc space group. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 11-coordinate geometry to two equivalent Fe(2), four equivalent Fe(3), one Ge(2), and four equivalent Ge(1) atoms. In the second Fe site, Fe(2) is bonded in a 14-coordinate geometry to two equivalent Fe(2), six equivalent Fe(1), and six equivalent Ge(1) atoms. In the third Fe site, Fe(3) is bonded to two equivalent Fe(3), four equivalent Fe(1), two equivalent Ge(2), and four equivalent Ge(1) atoms to form a mixture of distorted corner, face, and edge-sharing FeFe6Ge6 cuboctahedra. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 8-coordinate geometry to two equivalent Fe(2), four equivalent Fe(1), and four equivalent Fe(3) atoms. In the second Ge site, Ge(2) is bonded in a 9-coordinate geometry to three equivalent Fe(1) and six equivalent Fe(3) atoms.
Fe7Ge4 crystallizes in the hexagonal P6_3/mmc space group. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 11-coordinate geometry to two equivalent Fe(2), four equivalent Fe(3), one Ge(2), and four equivalent Ge(1) atoms. Both Fe(1)-Fe(2) bond lengths are 2.55 Å. All Fe(1)-Fe(3) bond lengths are 2.69 Å. The Fe(1)-Ge(2) bond length is 2.44 Å. There are two shorter (2.47 Å) and two longer (2.52 Å) Fe(1)-Ge(1) bond lengths. In the second Fe site, Fe(2) is bonded in a 14-coordinate geometry to two equivalent Fe(2), six equivalent Fe(1), and six equivalent Ge(1) atoms. Both Fe(2)-Fe(2) bond lengths are 2.48 Å. All Fe(2)-Ge(1) bond lengths are 2.93 Å. In the third Fe site, Fe(3) is bonded to two equivalent Fe(3), four equivalent Fe(1), two equivalent Ge(2), and four equivalent Ge(1) atoms to form a mixture of distorted corner, face, and edge-sharing FeFe6Ge6 cuboctahedra. Both Fe(3)-Fe(3) bond lengths are 2.48 Å. Both Fe(3)-Ge(2) bond lengths are 2.64 Å. All Fe(3)-Ge(1) bond lengths are 2.52 Å. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 8-coordinate geometry to two equivalent Fe(2), four equivalent Fe(1), and four equivalent Fe(3) atoms. In the second Ge site, Ge(2) is bonded in a 9-coordinate geometry to three equivalent Fe(1) and six equivalent Fe(3) atoms.