Mg11Tb17Ni8 crystallizes in the orthorhombic Pmmm space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 9-coordinate geometry to one Mg(1), four equivalent Tb(1), and four equivalent Tb(5) atoms. In the second Mg site, Mg(2) is bonded in a 9-coordinate geometry to one Mg(2), four equivalent Tb(2), and four equivalent Tb(6) atoms. In the third Mg site, Mg(3) is bonded in a 10-coordinate geometry to one Mg(3), two equivalent Tb(1), two equivalent Tb(2), two equivalent Tb(3), two equivalent Tb(4), and one Ni(2) atom. In the fourth Mg site, Mg(4) is bonded in a body-centered cubic geometry to four equivalent Tb(1) and four equivalent Tb(2) atoms. In the fifth Mg site, Mg(5) is bonded in a distorted square co-planar geometry to four equivalent Ni(2) atoms. There are seven inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a distorted L-shaped geometry to two equivalent Mg(1), two equivalent Mg(3), two equivalent Mg(4), and two equivalent Ni(1) atoms. In the second Tb site, Tb(2) is bonded in a distorted L-shaped geometry to two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and two equivalent Ni(2) atoms. In the third Tb site, Tb(3) is bonded in a 4-coordinate geometry to four equivalent Mg(3) and four equivalent Ni(1) atoms. In the fourth Tb site, Tb(4) is bonded in a 4-coordinate geometry to four equivalent Mg(3) and four equivalent Ni(2) atoms. In the fifth Tb site, Tb(5) is bonded in a 4-coordinate geometry to four equivalent Mg(1) and four equivalent Ni(1) atoms. In the sixth Tb site, Tb(6) is bonded in a 4-coordinate geometry to four equivalent Mg(2) and four equivalent Ni(2) atoms. In the seventh Tb site, Tb(7) is bonded in a square co-planar geometry to four equivalent Ni(1) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 7-coordinate geometry to one Tb(7), two equivalent Tb(1), two equivalent Tb(3), and two equivalent Tb(5) atoms. In the second Ni site, Ni(2) is bonded in a 7-coordinate geometry to one Mg(3), one Mg(5), two equivalent Tb(2), two equivalent Tb(4), and two equivalent Tb(6) atoms.
Mg11Tb17Ni8 crystallizes in the orthorhombic Pmmm space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 9-coordinate geometry to one Mg(1), four equivalent Tb(1), and four equivalent Tb(5) atoms. The Mg(1)-Mg(1) bond length is 3.19 Å. All Mg(1)-Tb(1) bond lengths are 3.32 Å. All Mg(1)-Tb(5) bond lengths are 3.42 Å. In the second Mg site, Mg(2) is bonded in a 9-coordinate geometry to one Mg(2), four equivalent Tb(2), and four equivalent Tb(6) atoms. The Mg(2)-Mg(2) bond length is 2.98 Å. All Mg(2)-Tb(2) bond lengths are 3.29 Å. All Mg(2)-Tb(6) bond lengths are 3.53 Å. In the third Mg site, Mg(3) is bonded in a 10-coordinate geometry to one Mg(3), two equivalent Tb(1), two equivalent Tb(2), two equivalent Tb(3), two equivalent Tb(4), and one Ni(2) atom. The Mg(3)-Mg(3) bond length is 3.07 Å. Both Mg(3)-Tb(1) bond lengths are 3.33 Å. Both Mg(3)-Tb(2) bond lengths are 3.28 Å. Both Mg(3)-Tb(3) bond lengths are 3.48 Å. Both Mg(3)-Tb(4) bond lengths are 3.48 Å. The Mg(3)-Ni(2) bond length is 3.29 Å. In the fourth Mg site, Mg(4) is bonded in a body-centered cubic geometry to four equivalent Tb(1) and four equivalent Tb(2) atoms. All Mg(4)-Tb(1) bond lengths are 3.29 Å. All Mg(4)-Tb(2) bond lengths are 3.27 Å. In the fifth Mg site, Mg(5) is bonded in a distorted square co-planar geometry to four equivalent Ni(2) atoms. All Mg(5)-Ni(2) bond lengths are 2.96 Å. There are seven inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a distorted L-shaped geometry to two equivalent Mg(1), two equivalent Mg(3), two equivalent Mg(4), and two equivalent Ni(1) atoms. Both Tb(1)-Ni(1) bond lengths are 2.72 Å. In the second Tb site, Tb(2) is bonded in a distorted L-shaped geometry to two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and two equivalent Ni(2) atoms. Both Tb(2)-Ni(2) bond lengths are 2.71 Å. In the third Tb site, Tb(3) is bonded in a 4-coordinate geometry to four equivalent Mg(3) and four equivalent Ni(1) atoms. All Tb(3)-Ni(1) bond lengths are 2.90 Å. In the fourth Tb site, Tb(4) is bonded in a 4-coordinate geometry to four equivalent Mg(3) and four equivalent Ni(2) atoms. All Tb(4)-Ni(2) bond lengths are 2.85 Å. In the fifth Tb site, Tb(5) is bonded in a 4-coordinate geometry to four equivalent Mg(1) and four equivalent Ni(1) atoms. All Tb(5)-Ni(1) bond lengths are 2.90 Å. In the sixth Tb site, Tb(6) is bonded in a 4-coordinate geometry to four equivalent Mg(2) and four equivalent Ni(2) atoms. All Tb(6)-Ni(2) bond lengths are 2.86 Å. In the seventh Tb site, Tb(7) is bonded in a square co-planar geometry to four equivalent Ni(1) atoms. All Tb(7)-Ni(1) bond lengths are 2.91 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 7-coordinate geometry to one Tb(7), two equivalent Tb(1), two equivalent Tb(3), and two equivalent Tb(5) atoms. In the second Ni site, Ni(2) is bonded in a 7-coordinate geometry to one Mg(3), one Mg(5), two equivalent Tb(2), two equivalent Tb(4), and two equivalent Tb(6) atoms.