Tb3FeSi6 crystallizes in the orthorhombic Amm2 space group. There are six inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 13-coordinate geometry to two equivalent Fe(1), one Si(7), two equivalent Si(3), four equivalent Si(10), and four equivalent Si(4) atoms. In the second Tb site, Tb(2) is bonded in a 13-coordinate geometry to two equivalent Fe(2), one Si(8), two equivalent Si(1), four equivalent Si(11), and four equivalent Si(5) atoms. In the third Tb site, Tb(3) is bonded in a 11-coordinate geometry to one Si(9), two equivalent Si(2), four equivalent Si(12), and four equivalent Si(6) atoms. In the fourth Tb site, Tb(4) is bonded in a 13-coordinate geometry to two equivalent Fe(1), one Si(10), two equivalent Si(5), four equivalent Si(1), and four equivalent Si(7) atoms. In the fifth Tb site, Tb(5) is bonded in a 13-coordinate geometry to two equivalent Fe(2), one Si(11), two equivalent Si(6), four equivalent Si(2), and four equivalent Si(8) atoms. In the sixth Tb site, Tb(6) is bonded in a 11-coordinate geometry to one Si(12), two equivalent Si(4), four equivalent Si(3), and four equivalent Si(9) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 8-coordinate geometry to two equivalent Tb(1), two equivalent Tb(4), two equivalent Si(10), and two equivalent Si(7) atoms. In the second Fe site, Fe(2) is bonded in a 8-coordinate geometry to two equivalent Tb(2), two equivalent Tb(5), two equivalent Si(11), and two equivalent Si(8) atoms. There are twelve inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Tb(2), four equivalent Tb(4), one Si(7), and two equivalent Si(5) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Tb(3), four equivalent Tb(5), one Si(8), and two equivalent Si(6) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to two equivalent Tb(1), four equivalent Tb(6), one Si(9), and two equivalent Si(4) atoms. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to two equivalent Tb(6), four equivalent Tb(1), one Si(10), and two equivalent Si(3) atoms. In the fifth Si site, Si(5) is bonded in a 9-coordinate geometry to two equivalent Tb(4), four equivalent Tb(2), one Si(11), and two equivalent Si(1) atoms. In the sixth Si site, Si(6) is bonded in a 9-coordinate geometry to two equivalent Tb(5), four equivalent Tb(3), one Si(12), and two equivalent Si(2) atoms. In the seventh Si site, Si(7) is bonded in a 8-coordinate geometry to one Tb(1), four equivalent Tb(4), two equivalent Fe(1), and one Si(1) atom. In the eighth Si site, Si(8) is bonded in a 8-coordinate geometry to one Tb(2), four equivalent Tb(5), two equivalent Fe(2), and one Si(2) atom. In the ninth Si site, Si(9) is bonded in a distorted hexagonal planar geometry to one Tb(3), four equivalent Tb(6), and one Si(3) atom. In the tenth Si site, Si(10) is bonded in a 8-coordinate geometry to one Tb(4), four equivalent Tb(1), two equivalent Fe(1), and one Si(4) atom. In the eleventh Si site, Si(11) is bonded in a 8-coordinate geometry to one Tb(5), four equivalent Tb(2), two equivalent Fe(2), and one Si(5) atom. In the twelfth Si site, Si(12) is bonded in a distorted hexagonal planar geometry to one Tb(6), four equivalent Tb(3), and one Si(6) atom.
Tb3FeSi6 crystallizes in the orthorhombic Amm2 space group. There are six inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 13-coordinate geometry to two equivalent Fe(1), one Si(7), two equivalent Si(3), four equivalent Si(10), and four equivalent Si(4) atoms. Both Tb(1)-Fe(1) bond lengths are 2.97 Å. The Tb(1)-Si(7) bond length is 3.15 Å. Both Tb(1)-Si(3) bond lengths are 3.16 Å. All Tb(1)-Si(10) bond lengths are 3.12 Å. All Tb(1)-Si(4) bond lengths are 3.05 Å. In the second Tb site, Tb(2) is bonded in a 13-coordinate geometry to two equivalent Fe(2), one Si(8), two equivalent Si(1), four equivalent Si(11), and four equivalent Si(5) atoms. Both Tb(2)-Fe(2) bond lengths are 3.02 Å. The Tb(2)-Si(8) bond length is 3.19 Å. Both Tb(2)-Si(1) bond lengths are 3.06 Å. All Tb(2)-Si(11) bond lengths are 3.15 Å. All Tb(2)-Si(5) bond lengths are 3.02 Å. In the third Tb site, Tb(3) is bonded in a 11-coordinate geometry to one Si(9), two equivalent Si(2), four equivalent Si(12), and four equivalent Si(6) atoms. The Tb(3)-Si(9) bond length is 3.12 Å. Both Tb(3)-Si(2) bond lengths are 3.09 Å. All Tb(3)-Si(12) bond lengths are 3.14 Å. All Tb(3)-Si(6) bond lengths are 3.00 Å. In the fourth Tb site, Tb(4) is bonded in a 13-coordinate geometry to two equivalent Fe(1), one Si(10), two equivalent Si(5), four equivalent Si(1), and four equivalent Si(7) atoms. Both Tb(4)-Fe(1) bond lengths are 3.01 Å. The Tb(4)-Si(10) bond length is 3.14 Å. Both Tb(4)-Si(5) bond lengths are 3.14 Å. All Tb(4)-Si(1) bond lengths are 3.05 Å. All Tb(4)-Si(7) bond lengths are 3.11 Å. In the fifth Tb site, Tb(5) is bonded in a 13-coordinate geometry to two equivalent Fe(2), one Si(11), two equivalent Si(6), four equivalent Si(2), and four equivalent Si(8) atoms. Both Tb(5)-Fe(2) bond lengths are 3.02 Å. The Tb(5)-Si(11) bond length is 3.15 Å. Both Tb(5)-Si(6) bond lengths are 3.17 Å. All Tb(5)-Si(2) bond lengths are 3.04 Å. All Tb(5)-Si(8) bond lengths are 3.13 Å. In the sixth Tb site, Tb(6) is bonded in a 11-coordinate geometry to one Si(12), two equivalent Si(4), four equivalent Si(3), and four equivalent Si(9) atoms. The Tb(6)-Si(12) bond length is 2.99 Å. Both Tb(6)-Si(4) bond lengths are 3.18 Å. All Tb(6)-Si(3) bond lengths are 3.05 Å. All Tb(6)-Si(9) bond lengths are 3.09 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 8-coordinate geometry to two equivalent Tb(1), two equivalent Tb(4), two equivalent Si(10), and two equivalent Si(7) atoms. Both Fe(1)-Si(10) bond lengths are 2.19 Å. Both Fe(1)-Si(7) bond lengths are 2.23 Å. In the second Fe site, Fe(2) is bonded in a 8-coordinate geometry to two equivalent Tb(2), two equivalent Tb(5), two equivalent Si(11), and two equivalent Si(8) atoms. Both Fe(2)-Si(11) bond lengths are 2.19 Å. Both Fe(2)-Si(8) bond lengths are 2.22 Å. There are twelve inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Tb(2), four equivalent Tb(4), one Si(7), and two equivalent Si(5) atoms. The Si(1)-Si(7) bond length is 2.41 Å. Both Si(1)-Si(5) bond lengths are 2.38 Å. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Tb(3), four equivalent Tb(5), one Si(8), and two equivalent Si(6) atoms. The Si(2)-Si(8) bond length is 2.41 Å. Both Si(2)-Si(6) bond lengths are 2.42 Å. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to two equivalent Tb(1), four equivalent Tb(6), one Si(9), and two equivalent Si(4) atoms. The Si(3)-Si(9) bond length is 2.35 Å. Both Si(3)-Si(4) bond lengths are 2.40 Å. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to two equivalent Tb(6), four equivalent Tb(1), one Si(10), and two equivalent Si(3) atoms. The Si(4)-Si(10) bond length is 2.41 Å. In the fifth Si site, Si(5) is bonded in a 9-coordinate geometry to two equivalent Tb(4), four equivalent Tb(2), one Si(11), and two equivalent Si(1) atoms. The Si(5)-Si(11) bond length is 2.38 Å. In the sixth Si site, Si(6) is bonded in a 9-coordinate geometry to two equivalent Tb(5), four equivalent Tb(3), one Si(12), and two equivalent Si(2) atoms. The Si(6)-Si(12) bond length is 2.32 Å. In the seventh Si site, Si(7) is bonded in a 8-coordinate geometry to one Tb(1), four equivalent Tb(4), two equivalent Fe(1), and one Si(1) atom. In the eighth Si site, Si(8) is bonded in a 8-coordinate geometry to one Tb(2), four equivalent Tb(5), two equivalent Fe(2), and one Si(2) atom. In the ninth Si site, Si(9) is bonded in a distorted hexagonal planar geometry to one Tb(3), four equivalent Tb(6), and one Si(3) atom. In the tenth Si site, Si(10) is bonded in a 8-coordinate geometry to one Tb(4), four equivalent Tb(1), two equivalent Fe(1), and one Si(4) atom. In the eleventh Si site, Si(11) is bonded in a 8-coordinate geometry to one Tb(5), four equivalent Tb(2), two equivalent Fe(2), and one Si(5) atom. In the twelfth Si site, Si(12) is bonded in a distorted hexagonal planar geometry to one Tb(6), four equivalent Tb(3), and one Si(6) atom.