Co19Nd5 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 Co(3) and twelve equivalent Co(6) atoms. In the second Nd site, Nd(2) is bonded in a 18-coordinate geometry to three equivalent Co(2), three equivalent Co(4), six equivalent Co(5), and six equivalent Co(6) atoms. In the third Nd site, Nd(3) is bonded in a 12-coordinate geometry to three equivalent Co(1) and nine equivalent Co(5) atoms. There are six inequivalent Co sites. In the first Co site, Co(1) is bonded to six equivalent Nd(3) and six equivalent Co(5) atoms to form CoNd6Co6 cuboctahedra that share corners with twelve equivalent Co(5)Nd5Co7 cuboctahedra, edges with six equivalent Co(1)Nd6Co6 cuboctahedra, and faces with eighteen equivalent Co(5)Nd5Co7 cuboctahedra. In the second Co site, Co(2) is bonded in a 9-coordinate geometry to three equivalent Nd(2), three equivalent Co(5), and three equivalent Co(6) atoms. In the third Co site, Co(3) is bonded in a 9-coordinate geometry to three equivalent Nd(1) and six equivalent Co(6) atoms. In the fourth Co site, Co(4) is bonded in a 9-coordinate geometry to three equivalent Nd(2), three equivalent Co(5), and three equivalent Co(6) atoms. In the fifth Co site, Co(5) is bonded to two equivalent Nd(2), three equivalent Nd(3), one Co(1), one Co(2), one Co(4), and four equivalent Co(5) atoms to form distorted CoNd5Co7 cuboctahedra that share corners with two equivalent Co(1)Nd6Co6 cuboctahedra, corners with six equivalent Co(6)Nd4Co8 cuboctahedra, corners with nine equivalent Co(5)Nd5Co7 cuboctahedra, edges with four equivalent Co(6)Nd4Co8 cuboctahedra, edges with four equivalent Co(5)Nd5Co7 cuboctahedra,  a faceface with one Co(6)Nd4Co8 cuboctahedra, faces with three equivalent Co(1)Nd6Co6 cuboctahedra, and faces with ten equivalent Co(5)Nd5Co7 cuboctahedra. In the sixth Co site, Co(6) is bonded to two equivalent Nd(1), two equivalent Nd(2), one Co(2), one Co(4), two equivalent Co(3), and four equivalent Co(6) atoms to form CoNd4Co8 cuboctahedra that share corners with six equivalent Co(5)Nd5Co7 cuboctahedra, corners with ten equivalent Co(6)Nd4Co8 cuboctahedra, edges with four equivalent Co(5)Nd5Co7 cuboctahedra, edges with six equivalent Co(6)Nd4Co8 cuboctahedra,  a faceface with one Co(5)Nd5Co7 cuboctahedra, and faces with nine equivalent Co(6)Nd4Co8 cuboctahedra.
Co19Nd5 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 Co(3) and twelve equivalent Co(6) atoms. All Nd(1)-Co(3) bond lengths are 2.91 Å. All Nd(1)-Co(6) bond lengths are 3.20 Å. In the second Nd site, Nd(2) is bonded in a 18-coordinate geometry to three equivalent Co(2), three equivalent Co(4), six equivalent Co(5), and six equivalent Co(6) atoms. All Nd(2)-Co(2) bond lengths are 2.91 Å. All Nd(2)-Co(4) bond lengths are 2.91 Å. All Nd(2)-Co(5) bond lengths are 3.27 Å. All Nd(2)-Co(6) bond lengths are 3.13 Å. In the third Nd site, Nd(3) is bonded in a 12-coordinate geometry to three equivalent Co(1) and nine equivalent Co(5) atoms. All Nd(3)-Co(1) bond lengths are 2.98 Å. There are six shorter (2.93 Å) and three longer (3.21 Å) Nd(3)-Co(5) bond lengths. There are six inequivalent Co sites. In the first Co site, Co(1) is bonded to six equivalent Nd(3) and six equivalent Co(5) atoms to form CoNd6Co6 cuboctahedra that share corners with twelve equivalent Co(5)Nd5Co7 cuboctahedra, edges with six equivalent Co(1)Nd6Co6 cuboctahedra, and faces with eighteen equivalent Co(5)Nd5Co7 cuboctahedra. All Co(1)-Co(5) bond lengths are 2.61 Å. In the second Co site, Co(2) is bonded in a 9-coordinate geometry to three equivalent Nd(2), three equivalent Co(5), and three equivalent Co(6) atoms. All Co(2)-Co(5) bond lengths are 2.43 Å. All Co(2)-Co(6) bond lengths are 2.49 Å. In the third Co site, Co(3) is bonded in a 9-coordinate geometry to three equivalent Nd(1) and six equivalent Co(6) atoms. There are three shorter (2.44 Å) and three longer (2.46 Å) Co(3)-Co(6) bond lengths. In the fourth Co site, Co(4) is bonded in a 9-coordinate geometry to three equivalent Nd(2), three equivalent Co(5), and three equivalent Co(6) atoms. All Co(4)-Co(5) bond lengths are 2.44 Å. All Co(4)-Co(6) bond lengths are 2.46 Å. In the fifth Co site, Co(5) is bonded to two equivalent Nd(2), three equivalent Nd(3), one Co(1), one Co(2), one Co(4), and four equivalent Co(5) atoms to form distorted CoNd5Co7 cuboctahedra that share corners with two equivalent Co(1)Nd6Co6 cuboctahedra, corners with six equivalent Co(6)Nd4Co8 cuboctahedra, corners with nine equivalent Co(5)Nd5Co7 cuboctahedra, edges with four equivalent Co(6)Nd4Co8 cuboctahedra, edges with four equivalent Co(5)Nd5Co7 cuboctahedra,  a faceface with one Co(6)Nd4Co8 cuboctahedra, faces with three equivalent Co(1)Nd6Co6 cuboctahedra, and faces with ten equivalent Co(5)Nd5Co7 cuboctahedra. There are two shorter (2.49 Å) and two longer (2.55 Å) Co(5)-Co(5) bond lengths. In the sixth Co site, Co(6) is bonded to two equivalent Nd(1), two equivalent Nd(2), one Co(2), one Co(4), two equivalent Co(3), and four equivalent Co(6) atoms to form CoNd4Co8 cuboctahedra that share corners with six equivalent Co(5)Nd5Co7 cuboctahedra, corners with ten equivalent Co(6)Nd4Co8 cuboctahedra, edges with four equivalent Co(5)Nd5Co7 cuboctahedra, edges with six equivalent Co(6)Nd4Co8 cuboctahedra,  a faceface with one Co(5)Nd5Co7 cuboctahedra, and faces with nine equivalent Co(6)Nd4Co8 cuboctahedra. There are two shorter (2.51 Å) and two longer (2.52 Å) Co(6)-Co(6) bond lengths.