Tm3Ni7B2 crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded in a 12-coordinate geometry to one Tm(2), three equivalent Ni(1), and nine equivalent Ni(2) atoms. In the second Tm site, Tm(2) is bonded in a 20-coordinate geometry to two equivalent Tm(1), twelve equivalent Ni(2), three equivalent B(1), and three equivalent B(2) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to six equivalent Tm(1) and six equivalent Ni(2) atoms to form edge-sharing NiTm6Ni6 cuboctahedra. In the second Ni site, Ni(2) is bonded in a distorted L-shaped geometry to two equivalent Tm(2), three equivalent Tm(1), one Ni(1), one B(1), and one B(2) atom. There are two inequivalent B sites. In the first B site, B(1) is bonded in a 6-coordinate geometry to three equivalent Tm(2) and six equivalent Ni(2) atoms. In the second B site, B(2) is bonded in a 6-coordinate geometry to three equivalent Tm(2) and six equivalent Ni(2) atoms.
Tm3Ni7B2 crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded in a 12-coordinate geometry to one Tm(2), three equivalent Ni(1), and nine equivalent Ni(2) atoms. The Tm(1)-Tm(2) bond length is 3.10 Å. All Tm(1)-Ni(1) bond lengths are 2.94 Å. There are three shorter (2.95 Å) and six longer (3.01 Å) Tm(1)-Ni(2) bond lengths. In the second Tm site, Tm(2) is bonded in a 20-coordinate geometry to two equivalent Tm(1), twelve equivalent Ni(2), three equivalent B(1), and three equivalent B(2) atoms. All Tm(2)-Ni(2) bond lengths are 2.90 Å. All Tm(2)-B(1) bond lengths are 2.90 Å. All Tm(2)-B(2) bond lengths are 2.90 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to six equivalent Tm(1) and six equivalent Ni(2) atoms to form edge-sharing NiTm6Ni6 cuboctahedra. All Ni(1)-Ni(2) bond lengths are 2.56 Å. In the second Ni site, Ni(2) is bonded in a distorted L-shaped geometry to two equivalent Tm(2), three equivalent Tm(1), one Ni(1), one B(1), and one B(2) atom. The Ni(2)-B(1) bond length is 2.06 Å. The Ni(2)-B(2) bond length is 2.05 Å. There are two inequivalent B sites. In the first B site, B(1) is bonded in a 6-coordinate geometry to three equivalent Tm(2) and six equivalent Ni(2) atoms. In the second B site, B(2) is bonded in a 6-coordinate geometry to three equivalent Tm(2) and six equivalent Ni(2) atoms.