Tb4FeGe8 crystallizes in the orthorhombic Pmm2 space group. There are four inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 10-coordinate geometry to two equivalent Ge(1), two equivalent Ge(3), two equivalent Ge(6), and four equivalent Ge(7) atoms. In the second Tb site, Tb(2) is bonded in a 10-coordinate geometry to two equivalent Ge(2), two equivalent Ge(4), two equivalent Ge(5), and four equivalent Ge(8) atoms. In the third Tb site, Tb(3) is bonded in a 14-coordinate geometry to four equivalent Fe(1), two equivalent Ge(1), two equivalent Ge(3), two equivalent Ge(8), and four equivalent Ge(5) atoms. In the fourth Tb site, Tb(4) is bonded in a 10-coordinate geometry to two equivalent Ge(2), two equivalent Ge(4), two equivalent Ge(7), and four equivalent Ge(6) atoms. Fe(1) is bonded in a 5-coordinate geometry to four equivalent Tb(3), one Ge(5), two equivalent Ge(1), and two equivalent Ge(3) atoms. There are eight inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 10-coordinate geometry to two equivalent Tb(1), two equivalent Tb(3), two equivalent Fe(1), and four equivalent Ge(3) atoms. In the second Ge site, Ge(2) is bonded in a 8-coordinate geometry to two equivalent Tb(2), two equivalent Tb(4), and four equivalent Ge(4) atoms. In the third Ge site, Ge(3) is bonded in a 4-coordinate geometry to two equivalent Tb(1), two equivalent Tb(3), two equivalent Fe(1), and four equivalent Ge(1) atoms. In the fourth Ge site, Ge(4) is bonded in a 8-coordinate geometry to two equivalent Tb(2), two equivalent Tb(4), and four equivalent Ge(2) atoms. In the fifth Ge site, Ge(5) is bonded in a 9-coordinate geometry to two equivalent Tb(2), four equivalent Tb(3), one Fe(1), and two equivalent Ge(8) atoms. In the sixth Ge site, Ge(6) is bonded in a 8-coordinate geometry to two equivalent Tb(1), four equivalent Tb(4), and two equivalent Ge(7) atoms. In the seventh Ge site, Ge(7) is bonded in a 8-coordinate geometry to two equivalent Tb(4), four equivalent Tb(1), and two equivalent Ge(6) atoms. In the eighth Ge site, Ge(8) is bonded in a 8-coordinate geometry to two equivalent Tb(3), four equivalent Tb(2), and two equivalent Ge(5) atoms.
Tb4FeGe8 crystallizes in the orthorhombic Pmm2 space group. There are four inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 10-coordinate geometry to two equivalent Ge(1), two equivalent Ge(3), two equivalent Ge(6), and four equivalent Ge(7) atoms. Both Tb(1)-Ge(1) bond lengths are 3.04 Å. Both Tb(1)-Ge(3) bond lengths are 2.98 Å. Both Tb(1)-Ge(6) bond lengths are 3.22 Å. All Tb(1)-Ge(7) bond lengths are 2.98 Å. In the second Tb site, Tb(2) is bonded in a 10-coordinate geometry to two equivalent Ge(2), two equivalent Ge(4), two equivalent Ge(5), and four equivalent Ge(8) atoms. Both Tb(2)-Ge(2) bond lengths are 3.10 Å. Both Tb(2)-Ge(4) bond lengths are 3.08 Å. Both Tb(2)-Ge(5) bond lengths are 3.19 Å. All Tb(2)-Ge(8) bond lengths are 2.99 Å. In the third Tb site, Tb(3) is bonded in a 14-coordinate geometry to four equivalent Fe(1), two equivalent Ge(1), two equivalent Ge(3), two equivalent Ge(8), and four equivalent Ge(5) atoms. All Tb(3)-Fe(1) bond lengths are 3.21 Å. Both Tb(3)-Ge(1) bond lengths are 3.20 Å. Both Tb(3)-Ge(3) bond lengths are 3.27 Å. Both Tb(3)-Ge(8) bond lengths are 3.29 Å. All Tb(3)-Ge(5) bond lengths are 3.02 Å. In the fourth Tb site, Tb(4) is bonded in a 10-coordinate geometry to two equivalent Ge(2), two equivalent Ge(4), two equivalent Ge(7), and four equivalent Ge(6) atoms. Both Tb(4)-Ge(2) bond lengths are 3.09 Å. Both Tb(4)-Ge(4) bond lengths are 3.11 Å. Both Tb(4)-Ge(7) bond lengths are 3.28 Å. All Tb(4)-Ge(6) bond lengths are 3.00 Å. Fe(1) is bonded in a 5-coordinate geometry to four equivalent Tb(3), one Ge(5), two equivalent Ge(1), and two equivalent Ge(3) atoms. The Fe(1)-Ge(5) bond length is 2.32 Å. Both Fe(1)-Ge(1) bond lengths are 2.35 Å. Both Fe(1)-Ge(3) bond lengths are 2.29 Å. There are eight inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 10-coordinate geometry to two equivalent Tb(1), two equivalent Tb(3), two equivalent Fe(1), and four equivalent Ge(3) atoms. All Ge(1)-Ge(3) bond lengths are 2.88 Å. In the second Ge site, Ge(2) is bonded in a 8-coordinate geometry to two equivalent Tb(2), two equivalent Tb(4), and four equivalent Ge(4) atoms. All Ge(2)-Ge(4) bond lengths are 2.88 Å. In the third Ge site, Ge(3) is bonded in a 4-coordinate geometry to two equivalent Tb(1), two equivalent Tb(3), two equivalent Fe(1), and four equivalent Ge(1) atoms. In the fourth Ge site, Ge(4) is bonded in a 8-coordinate geometry to two equivalent Tb(2), two equivalent Tb(4), and four equivalent Ge(2) atoms. In the fifth Ge site, Ge(5) is bonded in a 9-coordinate geometry to two equivalent Tb(2), four equivalent Tb(3), one Fe(1), and two equivalent Ge(8) atoms. Both Ge(5)-Ge(8) bond lengths are 2.58 Å. In the sixth Ge site, Ge(6) is bonded in a 8-coordinate geometry to two equivalent Tb(1), four equivalent Tb(4), and two equivalent Ge(7) atoms. Both Ge(6)-Ge(7) bond lengths are 2.62 Å. In the seventh Ge site, Ge(7) is bonded in a 8-coordinate geometry to two equivalent Tb(4), four equivalent Tb(1), and two equivalent Ge(6) atoms. In the eighth Ge site, Ge(8) is bonded in a 8-coordinate geometry to two equivalent Tb(3), four equivalent Tb(2), and two equivalent Ge(5) atoms.