TbFe6Sn4Ge2 crystallizes in the hexagonal P6/mmm space group. Tb(1) is bonded to twelve equivalent Fe(1), two equivalent Sn(2), and six equivalent Ge(1) atoms to form distorted TbFe12Sn2Ge6 hexagonal bipyramids that share faces with twenty-four equivalent Fe(1)Tb2Fe4Sn4Ge2 cuboctahedra and faces with six equivalent Tb(1)Fe12Sn2Ge6 hexagonal bipyramids. Fe(1) is bonded to two equivalent Tb(1), four equivalent Fe(1), two equivalent Sn(1), two equivalent Sn(2), and two equivalent Ge(1) atoms to form distorted FeTb2Fe4Sn4Ge2 cuboctahedra that share corners with fourteen equivalent Fe(1)Tb2Fe4Sn4Ge2 cuboctahedra, edges with seven equivalent Fe(1)Tb2Fe4Sn4Ge2 cuboctahedra, faces with nine equivalent Fe(1)Tb2Fe4Sn4Ge2 cuboctahedra, and faces with four equivalent Tb(1)Fe12Sn2Ge6 hexagonal bipyramids. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a 6-coordinate geometry to six equivalent Fe(1) atoms. In the second Sn site, Sn(2) is bonded in a 8-coordinate geometry to one Tb(1), six equivalent Fe(1), and one Sn(2) atom. Ge(1) is bonded in a 9-coordinate geometry to three equivalent Tb(1) and six equivalent Fe(1) atoms.
TbFe6Sn4Ge2 crystallizes in the hexagonal P6/mmm space group. Tb(1) is bonded to twelve equivalent Fe(1), two equivalent Sn(2), and six equivalent Ge(1) atoms to form distorted TbFe12Sn2Ge6 hexagonal bipyramids that share faces with twenty-four equivalent Fe(1)Tb2Fe4Sn4Ge2 cuboctahedra and faces with six equivalent Tb(1)Fe12Sn2Ge6 hexagonal bipyramids. All Tb(1)-Fe(1) bond lengths are 3.34 Å. Both Tb(1)-Sn(2) bond lengths are 2.94 Å. All Tb(1)-Ge(1) bond lengths are 3.06 Å. Fe(1) is bonded to two equivalent Tb(1), four equivalent Fe(1), two equivalent Sn(1), two equivalent Sn(2), and two equivalent Ge(1) atoms to form distorted FeTb2Fe4Sn4Ge2 cuboctahedra that share corners with fourteen equivalent Fe(1)Tb2Fe4Sn4Ge2 cuboctahedra, edges with seven equivalent Fe(1)Tb2Fe4Sn4Ge2 cuboctahedra, faces with nine equivalent Fe(1)Tb2Fe4Sn4Ge2 cuboctahedra, and faces with four equivalent Tb(1)Fe12Sn2Ge6 hexagonal bipyramids. All Fe(1)-Fe(1) bond lengths are 2.65 Å. Both Fe(1)-Sn(1) bond lengths are 2.80 Å. Both Fe(1)-Sn(2) bond lengths are 2.81 Å. Both Fe(1)-Ge(1) bond lengths are 2.54 Å. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a 6-coordinate geometry to six equivalent Fe(1) atoms. In the second Sn site, Sn(2) is bonded in a 8-coordinate geometry to one Tb(1), six equivalent Fe(1), and one Sn(2) atom. The Sn(2)-Sn(2) bond length is 2.85 Å. Ge(1) is bonded in a 9-coordinate geometry to three equivalent Tb(1) and six equivalent Fe(1) atoms.