Nd5Ni19 crystallizes in the trigonal R-3m space group. There are three inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 18-coordinate geometry to six equivalent Ni(3) and twelve equivalent Ni(6) atoms. In the second Nd site, Nd(2) is bonded in a 18-coordinate geometry to three equivalent Ni(2), three equivalent Ni(4), six equivalent Ni(5), and six equivalent Ni(6) atoms. In the third Nd site, Nd(3) is bonded in a 12-coordinate geometry to three equivalent Ni(1) and nine equivalent Ni(5) atoms. There are six inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to six equivalent Nd(3) and six equivalent Ni(5) atoms to form NiNd6Ni6 cuboctahedra that share corners with twelve equivalent Ni(5)Nd5Ni7 cuboctahedra, edges with six equivalent Ni(1)Nd6Ni6 cuboctahedra, and faces with eighteen equivalent Ni(5)Nd5Ni7 cuboctahedra. In the second Ni site, Ni(2) is bonded in a 9-coordinate geometry to three equivalent Nd(2), three equivalent Ni(5), and three equivalent Ni(6) atoms. In the third Ni site, Ni(3) is bonded in a 9-coordinate geometry to three equivalent Nd(1) and six equivalent Ni(6) atoms. In the fourth Ni site, Ni(4) is bonded in a 9-coordinate geometry to three equivalent Nd(2), three equivalent Ni(5), and three equivalent Ni(6) atoms. In the fifth Ni site, Ni(5) is bonded to two equivalent Nd(2), three equivalent Nd(3), one Ni(1), one Ni(2), one Ni(4), and four equivalent Ni(5) atoms to form distorted NiNd5Ni7 cuboctahedra that share corners with two equivalent Ni(1)Nd6Ni6 cuboctahedra, corners with six equivalent Ni(6)Nd4Ni8 cuboctahedra, corners with nine equivalent Ni(5)Nd5Ni7 cuboctahedra, edges with four equivalent Ni(6)Nd4Ni8 cuboctahedra, edges with four equivalent Ni(5)Nd5Ni7 cuboctahedra,  a faceface with one Ni(6)Nd4Ni8 cuboctahedra, faces with three equivalent Ni(1)Nd6Ni6 cuboctahedra, and faces with ten equivalent Ni(5)Nd5Ni7 cuboctahedra. In the sixth Ni site, Ni(6) is bonded to two equivalent Nd(1), two equivalent Nd(2), one Ni(2), one Ni(4), two equivalent Ni(3), and four equivalent Ni(6) atoms to form NiNd4Ni8 cuboctahedra that share corners with six equivalent Ni(5)Nd5Ni7 cuboctahedra, corners with ten equivalent Ni(6)Nd4Ni8 cuboctahedra, edges with four equivalent Ni(5)Nd5Ni7 cuboctahedra, edges with six equivalent Ni(6)Nd4Ni8 cuboctahedra,  a faceface with one Ni(5)Nd5Ni7 cuboctahedra, and faces with nine equivalent Ni(6)Nd4Ni8 cuboctahedra.
Nd5Ni19 crystallizes in the trigonal R-3m space group. There are three inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 18-coordinate geometry to six equivalent Ni(3) and twelve equivalent Ni(6) atoms. All Nd(1)-Ni(3) bond lengths are 2.87 Å. All Nd(1)-Ni(6) bond lengths are 3.17 Å. In the second Nd site, Nd(2) is bonded in a 18-coordinate geometry to three equivalent Ni(2), three equivalent Ni(4), six equivalent Ni(5), and six equivalent Ni(6) atoms. All Nd(2)-Ni(2) bond lengths are 2.88 Å. All Nd(2)-Ni(4) bond lengths are 2.88 Å. All Nd(2)-Ni(5) bond lengths are 3.29 Å. All Nd(2)-Ni(6) bond lengths are 3.08 Å. In the third Nd site, Nd(3) is bonded in a 12-coordinate geometry to three equivalent Ni(1) and nine equivalent Ni(5) atoms. All Nd(3)-Ni(1) bond lengths are 2.96 Å. There are six shorter (2.86 Å) and three longer (3.20 Å) Nd(3)-Ni(5) bond lengths. There are six inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to six equivalent Nd(3) and six equivalent Ni(5) atoms to form NiNd6Ni6 cuboctahedra that share corners with twelve equivalent Ni(5)Nd5Ni7 cuboctahedra, edges with six equivalent Ni(1)Nd6Ni6 cuboctahedra, and faces with eighteen equivalent Ni(5)Nd5Ni7 cuboctahedra. All Ni(1)-Ni(5) bond lengths are 2.57 Å. In the second Ni site, Ni(2) is bonded in a 9-coordinate geometry to three equivalent Nd(2), three equivalent Ni(5), and three equivalent Ni(6) atoms. All Ni(2)-Ni(5) bond lengths are 2.43 Å. All Ni(2)-Ni(6) bond lengths are 2.46 Å. In the third Ni site, Ni(3) is bonded in a 9-coordinate geometry to three equivalent Nd(1) and six equivalent Ni(6) atoms. All Ni(3)-Ni(6) bond lengths are 2.43 Å. In the fourth Ni site, Ni(4) is bonded in a 9-coordinate geometry to three equivalent Nd(2), three equivalent Ni(5), and three equivalent Ni(6) atoms. All Ni(4)-Ni(5) bond lengths are 2.44 Å. All Ni(4)-Ni(6) bond lengths are 2.45 Å. In the fifth Ni site, Ni(5) is bonded to two equivalent Nd(2), three equivalent Nd(3), one Ni(1), one Ni(2), one Ni(4), and four equivalent Ni(5) atoms to form distorted NiNd5Ni7 cuboctahedra that share corners with two equivalent Ni(1)Nd6Ni6 cuboctahedra, corners with six equivalent Ni(6)Nd4Ni8 cuboctahedra, corners with nine equivalent Ni(5)Nd5Ni7 cuboctahedra, edges with four equivalent Ni(6)Nd4Ni8 cuboctahedra, edges with four equivalent Ni(5)Nd5Ni7 cuboctahedra,  a faceface with one Ni(6)Nd4Ni8 cuboctahedra, faces with three equivalent Ni(1)Nd6Ni6 cuboctahedra, and faces with ten equivalent Ni(5)Nd5Ni7 cuboctahedra. There are two shorter (2.48 Å) and two longer (2.50 Å) Ni(5)-Ni(5) bond lengths. In the sixth Ni site, Ni(6) is bonded to two equivalent Nd(1), two equivalent Nd(2), one Ni(2), one Ni(4), two equivalent Ni(3), and four equivalent Ni(6) atoms to form NiNd4Ni8 cuboctahedra that share corners with six equivalent Ni(5)Nd5Ni7 cuboctahedra, corners with ten equivalent Ni(6)Nd4Ni8 cuboctahedra, edges with four equivalent Ni(5)Nd5Ni7 cuboctahedra, edges with six equivalent Ni(6)Nd4Ni8 cuboctahedra,  a faceface with one Ni(5)Nd5Ni7 cuboctahedra, and faces with nine equivalent Ni(6)Nd4Ni8 cuboctahedra. All Ni(6)-Ni(6) bond lengths are 2.49 Å.