Yb2Ni17 crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Yb sites. In the first Yb site, Yb(1) is bonded in a 18-coordinate geometry to six equivalent Ni(3) and twelve equivalent Ni(4) atoms. In the second Yb site, Yb(2) is bonded in a 20-coordinate geometry to two equivalent Ni(1), six equivalent Ni(2), six equivalent Ni(3), and six equivalent Ni(4) atoms. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 14-coordinate geometry to one Yb(2), one Ni(1), three equivalent Ni(2), three equivalent Ni(4), and six equivalent Ni(3) atoms. In the second Ni site, Ni(2) is bonded to two equivalent Yb(2), two equivalent Ni(1), four equivalent Ni(3), and four equivalent Ni(4) atoms to form NiYb2Ni10 cuboctahedra that share corners with four equivalent Ni(2)Yb2Ni10 cuboctahedra, corners with ten equivalent Ni(4)Yb3Ni9 cuboctahedra, edges with six equivalent Ni(4)Yb3Ni9 cuboctahedra, faces with four equivalent Ni(4)Yb3Ni9 cuboctahedra, and faces with six equivalent Ni(2)Yb2Ni10 cuboctahedra. In the third Ni site, Ni(3) is bonded in a 12-coordinate geometry to one Yb(1), one Yb(2), two equivalent Ni(1), two equivalent Ni(2), two equivalent Ni(3), and four equivalent Ni(4) atoms. In the fourth Ni site, Ni(4) is bonded to one Yb(2), two equivalent Yb(1), one Ni(1), two equivalent Ni(2), two equivalent Ni(4), and four equivalent Ni(3) atoms to form distorted NiYb3Ni9 cuboctahedra that share corners with five equivalent Ni(2)Yb2Ni10 cuboctahedra, corners with ten equivalent Ni(4)Yb3Ni9 cuboctahedra, edges with three equivalent Ni(2)Yb2Ni10 cuboctahedra, edges with five equivalent Ni(4)Yb3Ni9 cuboctahedra, faces with two equivalent Ni(2)Yb2Ni10 cuboctahedra, and faces with eight equivalent Ni(4)Yb3Ni9 cuboctahedra.
Yb2Ni17 crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Yb sites. In the first Yb site, Yb(1) is bonded in a 18-coordinate geometry to six equivalent Ni(3) and twelve equivalent Ni(4) atoms. All Yb(1)-Ni(3) bond lengths are 2.87 Å. There are six shorter (2.99 Å) and six longer (3.19 Å) Yb(1)-Ni(4) bond lengths. In the second Yb site, Yb(2) is bonded in a 20-coordinate geometry to two equivalent Ni(1), six equivalent Ni(2), six equivalent Ni(3), and six equivalent Ni(4) atoms. Both Yb(2)-Ni(1) bond lengths are 2.80 Å. All Yb(2)-Ni(2) bond lengths are 3.10 Å. All Yb(2)-Ni(3) bond lengths are 2.95 Å. All Yb(2)-Ni(4) bond lengths are 3.01 Å. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 14-coordinate geometry to one Yb(2), one Ni(1), three equivalent Ni(2), three equivalent Ni(4), and six equivalent Ni(3) atoms. The Ni(1)-Ni(1) bond length is 2.36 Å. All Ni(1)-Ni(2) bond lengths are 2.51 Å. All Ni(1)-Ni(4) bond lengths are 2.58 Å. All Ni(1)-Ni(3) bond lengths are 2.70 Å. In the second Ni site, Ni(2) is bonded to two equivalent Yb(2), two equivalent Ni(1), four equivalent Ni(3), and four equivalent Ni(4) atoms to form NiYb2Ni10 cuboctahedra that share corners with four equivalent Ni(2)Yb2Ni10 cuboctahedra, corners with ten equivalent Ni(4)Yb3Ni9 cuboctahedra, edges with six equivalent Ni(4)Yb3Ni9 cuboctahedra, faces with four equivalent Ni(4)Yb3Ni9 cuboctahedra, and faces with six equivalent Ni(2)Yb2Ni10 cuboctahedra. All Ni(2)-Ni(3) bond lengths are 2.37 Å. All Ni(2)-Ni(4) bond lengths are 2.38 Å. In the third Ni site, Ni(3) is bonded in a 12-coordinate geometry to one Yb(1), one Yb(2), two equivalent Ni(1), two equivalent Ni(2), two equivalent Ni(3), and four equivalent Ni(4) atoms. There is one shorter (2.34 Å) and one longer (2.50 Å) Ni(3)-Ni(3) bond length. There are two shorter (2.47 Å) and two longer (2.49 Å) Ni(3)-Ni(4) bond lengths. In the fourth Ni site, Ni(4) is bonded to one Yb(2), two equivalent Yb(1), one Ni(1), two equivalent Ni(2), two equivalent Ni(4), and four equivalent Ni(3) atoms to form distorted NiYb3Ni9 cuboctahedra that share corners with five equivalent Ni(2)Yb2Ni10 cuboctahedra, corners with ten equivalent Ni(4)Yb3Ni9 cuboctahedra, edges with three equivalent Ni(2)Yb2Ni10 cuboctahedra, edges with five equivalent Ni(4)Yb3Ni9 cuboctahedra, faces with two equivalent Ni(2)Yb2Ni10 cuboctahedra, and faces with eight equivalent Ni(4)Yb3Ni9 cuboctahedra. Both Ni(4)-Ni(4) bond lengths are 2.38 Å.