Tb4CoSn8 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 Sn(2), two equivalent Sn(5), two equivalent Sn(7), and four equivalent Sn(3) atoms. In the second Tb site, Tb(2) is bonded in a 10-coordinate geometry to two equivalent Sn(1), two equivalent Sn(6), two equivalent Sn(8), and four equivalent Sn(4) atoms. In the third Tb site, Tb(3) is bonded in a 14-coordinate geometry to four equivalent Co(1), two equivalent Sn(4), two equivalent Sn(5), two equivalent Sn(7), and four equivalent Sn(1) atoms. In the fourth Tb site, Tb(4) is bonded in a 10-coordinate geometry to two equivalent Sn(3), two equivalent Sn(6), two equivalent Sn(8), and four equivalent Sn(2) atoms. Co(1) is bonded in a 5-coordinate geometry to four equivalent Tb(3), one Sn(1), two equivalent Sn(5), and two equivalent Sn(7) atoms. There are eight inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a 9-coordinate geometry to two equivalent Tb(2), four equivalent Tb(3), one Co(1), and two equivalent Sn(4) atoms. In the second Sn site, Sn(2) is bonded in a 8-coordinate geometry to two equivalent Tb(1), four equivalent Tb(4), and two equivalent Sn(3) atoms. In the third Sn site, Sn(3) is bonded in a 8-coordinate geometry to two equivalent Tb(4), four equivalent Tb(1), and two equivalent Sn(2) atoms. In the fourth Sn site, Sn(4) is bonded in a 8-coordinate geometry to two equivalent Tb(3), four equivalent Tb(2), and two equivalent Sn(1) atoms. In the fifth Sn site, Sn(5) is bonded in a 10-coordinate geometry to two equivalent Tb(1), two equivalent Tb(3), two equivalent Co(1), and four equivalent Sn(7) atoms. In the sixth Sn site, Sn(6) is bonded in a 8-coordinate geometry to two equivalent Tb(2), two equivalent Tb(4), and four equivalent Sn(8) atoms. In the seventh Sn site, Sn(7) is bonded in a 10-coordinate geometry to two equivalent Tb(1), two equivalent Tb(3), two equivalent Co(1), and four equivalent Sn(5) atoms. In the eighth Sn site, Sn(8) is bonded in a 8-coordinate geometry to two equivalent Tb(2), two equivalent Tb(4), and four equivalent Sn(6) atoms.
Tb4CoSn8 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 Sn(2), two equivalent Sn(5), two equivalent Sn(7), and four equivalent Sn(3) atoms. Both Tb(1)-Sn(2) bond lengths are 3.50 Å. Both Tb(1)-Sn(5) bond lengths are 3.22 Å. Both Tb(1)-Sn(7) bond lengths are 3.23 Å. All Tb(1)-Sn(3) bond lengths are 3.20 Å. In the second Tb site, Tb(2) is bonded in a 10-coordinate geometry to two equivalent Sn(1), two equivalent Sn(6), two equivalent Sn(8), and four equivalent Sn(4) atoms. Both Tb(2)-Sn(1) bond lengths are 3.35 Å. Both Tb(2)-Sn(6) bond lengths are 3.29 Å. Both Tb(2)-Sn(8) bond lengths are 3.34 Å. All Tb(2)-Sn(4) bond lengths are 3.18 Å. In the third Tb site, Tb(3) is bonded in a 14-coordinate geometry to four equivalent Co(1), two equivalent Sn(4), two equivalent Sn(5), two equivalent Sn(7), and four equivalent Sn(1) atoms. All Tb(3)-Co(1) bond lengths are 3.48 Å. Both Tb(3)-Sn(4) bond lengths are 3.68 Å. Both Tb(3)-Sn(5) bond lengths are 3.46 Å. Both Tb(3)-Sn(7) bond lengths are 3.45 Å. All Tb(3)-Sn(1) bond lengths are 3.28 Å. In the fourth Tb site, Tb(4) is bonded in a 10-coordinate geometry to two equivalent Sn(3), two equivalent Sn(6), two equivalent Sn(8), and four equivalent Sn(2) atoms. Both Tb(4)-Sn(3) bond lengths are 3.51 Å. Both Tb(4)-Sn(6) bond lengths are 3.36 Å. Both Tb(4)-Sn(8) bond lengths are 3.31 Å. All Tb(4)-Sn(2) bond lengths are 3.20 Å. Co(1) is bonded in a 5-coordinate geometry to four equivalent Tb(3), one Sn(1), two equivalent Sn(5), and two equivalent Sn(7) atoms. The Co(1)-Sn(1) bond length is 2.45 Å. Both Co(1)-Sn(5) bond lengths are 2.51 Å. Both Co(1)-Sn(7) bond lengths are 2.49 Å. There are eight inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a 9-coordinate geometry to two equivalent Tb(2), four equivalent Tb(3), one Co(1), and two equivalent Sn(4) atoms. Both Sn(1)-Sn(4) bond lengths are 2.97 Å. In the second Sn site, Sn(2) is bonded in a 8-coordinate geometry to two equivalent Tb(1), four equivalent Tb(4), and two equivalent Sn(3) atoms. Both Sn(2)-Sn(3) bond lengths are 3.04 Å. In the third Sn site, Sn(3) is bonded in a 8-coordinate geometry to two equivalent Tb(4), four equivalent Tb(1), and two equivalent Sn(2) atoms. In the fourth Sn site, Sn(4) is bonded in a 8-coordinate geometry to two equivalent Tb(3), four equivalent Tb(2), and two equivalent Sn(1) atoms. In the fifth Sn site, Sn(5) is bonded in a 10-coordinate geometry to two equivalent Tb(1), two equivalent Tb(3), two equivalent Co(1), and four equivalent Sn(7) atoms. All Sn(5)-Sn(7) bond lengths are 3.14 Å. In the sixth Sn site, Sn(6) is bonded in a 8-coordinate geometry to two equivalent Tb(2), two equivalent Tb(4), and four equivalent Sn(8) atoms. All Sn(6)-Sn(8) bond lengths are 3.14 Å. In the seventh Sn site, Sn(7) is bonded in a 10-coordinate geometry to two equivalent Tb(1), two equivalent Tb(3), two equivalent Co(1), and four equivalent Sn(5) atoms. In the eighth Sn site, Sn(8) is bonded in a 8-coordinate geometry to two equivalent Tb(2), two equivalent Tb(4), and four equivalent Sn(6) atoms.