Dy5Co19P12 crystallizes in the hexagonal P-62m space group. There are two inequivalent Dy sites. In the first Dy site, Dy(1) is bonded in a 15-coordinate geometry to three equivalent Co(2), six equivalent Co(3), and six equivalent P(2) atoms. In the second Dy site, Dy(2) is bonded in a 16-coordinate geometry to two equivalent Co(3), two equivalent Co(4), two equivalent Co(5), four equivalent Co(2), two equivalent P(1), and four equivalent P(3) atoms. There are five inequivalent Co sites. In the first Co site, Co(1) is bonded in a 5-coordinate geometry to one P(1) and four equivalent P(2) atoms. In the second Co site, Co(2) is bonded to one Dy(1), two equivalent Dy(2), one P(1), one P(3), and two equivalent P(2) atoms to form distorted CoDy3P4 tetrahedra that share corners with two equivalent Co(4)Dy2P4 tetrahedra, corners with two equivalent Co(3)Dy3P4 tetrahedra, corners with five equivalent Co(2)Dy3P4 tetrahedra, edges with two equivalent Co(2)Dy3P4 tetrahedra, edges with four equivalent Co(3)Dy3P4 tetrahedra,  a faceface with one Co(2)Dy3P4 tetrahedra, faces with two equivalent Co(4)Dy2P4 tetrahedra, and faces with two equivalent Co(3)Dy3P4 tetrahedra. In the third Co site, Co(3) is bonded to one Dy(2), two equivalent Dy(1), two equivalent P(1), and two equivalent P(2) atoms to form distorted CoDy3P4 tetrahedra that share corners with two equivalent Co(4)Dy2P4 tetrahedra, corners with two equivalent Co(2)Dy3P4 tetrahedra, corners with six equivalent Co(3)Dy3P4 tetrahedra,  an edgeedge with one Co(4)Dy2P4 tetrahedra, edges with two equivalent Co(3)Dy3P4 tetrahedra, edges with four equivalent Co(2)Dy3P4 tetrahedra, faces with two equivalent Co(2)Dy3P4 tetrahedra, and faces with three equivalent Co(3)Dy3P4 tetrahedra. In the fourth Co site, Co(4) is bonded to two equivalent Dy(2), two equivalent P(2), and two equivalent P(3) atoms to form distorted CoDy2P4 tetrahedra that share corners with four equivalent Co(4)Dy2P4 tetrahedra, corners with four equivalent Co(2)Dy3P4 tetrahedra, corners with four equivalent Co(3)Dy3P4 tetrahedra, edges with two equivalent Co(3)Dy3P4 tetrahedra, and faces with four equivalent Co(2)Dy3P4 tetrahedra. In the fifth Co site, Co(5) is bonded in a distorted trigonal planar geometry to six equivalent Dy(2) and three equivalent P(3) atoms. There are three inequivalent P sites. In the first P site, P(3) is bonded in a 9-coordinate geometry to four equivalent Dy(2), one Co(5), two equivalent Co(2), and two equivalent Co(4) atoms. In the second P site, P(1) is bonded in a 9-coordinate geometry to two equivalent Dy(2), one Co(1), two equivalent Co(2), and four equivalent Co(3) atoms. In the third P site, P(2) is bonded in a 9-coordinate geometry to two equivalent Dy(1), one Co(4), two equivalent Co(1), two equivalent Co(2), and two equivalent Co(3) atoms.
Dy5Co19P12 crystallizes in the hexagonal P-62m space group. There are two inequivalent Dy sites. In the first Dy site, Dy(1) is bonded in a 15-coordinate geometry to three equivalent Co(2), six equivalent Co(3), and six equivalent P(2) atoms. All Dy(1)-Co(2) bond lengths are 3.00 Å. All Dy(1)-Co(3) bond lengths are 2.99 Å. All Dy(1)-P(2) bond lengths are 2.81 Å. In the second Dy site, Dy(2) is bonded in a 16-coordinate geometry to two equivalent Co(3), two equivalent Co(4), two equivalent Co(5), four equivalent Co(2), two equivalent P(1), and four equivalent P(3) atoms. Both Dy(2)-Co(3) bond lengths are 3.08 Å. Both Dy(2)-Co(4) bond lengths are 3.01 Å. Both Dy(2)-Co(5) bond lengths are 2.89 Å. All Dy(2)-Co(2) bond lengths are 2.98 Å. Both Dy(2)-P(1) bond lengths are 2.84 Å. All Dy(2)-P(3) bond lengths are 2.87 Å. There are five inequivalent Co sites. In the first Co site, Co(1) is bonded in a 5-coordinate geometry to one P(1) and four equivalent P(2) atoms. The Co(1)-P(1) bond length is 2.20 Å. All Co(1)-P(2) bond lengths are 2.58 Å. In the second Co site, Co(2) is bonded to one Dy(1), two equivalent Dy(2), one P(1), one P(3), and two equivalent P(2) atoms to form distorted CoDy3P4 tetrahedra that share corners with two equivalent Co(4)Dy2P4 tetrahedra, corners with two equivalent Co(3)Dy3P4 tetrahedra, corners with five equivalent Co(2)Dy3P4 tetrahedra, edges with two equivalent Co(2)Dy3P4 tetrahedra, edges with four equivalent Co(3)Dy3P4 tetrahedra,  a faceface with one Co(2)Dy3P4 tetrahedra, faces with two equivalent Co(4)Dy2P4 tetrahedra, and faces with two equivalent Co(3)Dy3P4 tetrahedra. The Co(2)-P(1) bond length is 2.34 Å. The Co(2)-P(3) bond length is 2.25 Å. Both Co(2)-P(2) bond lengths are 2.25 Å. In the third Co site, Co(3) is bonded to one Dy(2), two equivalent Dy(1), two equivalent P(1), and two equivalent P(2) atoms to form distorted CoDy3P4 tetrahedra that share corners with two equivalent Co(4)Dy2P4 tetrahedra, corners with two equivalent Co(2)Dy3P4 tetrahedra, corners with six equivalent Co(3)Dy3P4 tetrahedra,  an edgeedge with one Co(4)Dy2P4 tetrahedra, edges with two equivalent Co(3)Dy3P4 tetrahedra, edges with four equivalent Co(2)Dy3P4 tetrahedra, faces with two equivalent Co(2)Dy3P4 tetrahedra, and faces with three equivalent Co(3)Dy3P4 tetrahedra. Both Co(3)-P(1) bond lengths are 2.34 Å. There is one shorter (2.22 Å) and one longer (2.28 Å) Co(3)-P(2) bond length. In the fourth Co site, Co(4) is bonded to two equivalent Dy(2), two equivalent P(2), and two equivalent P(3) atoms to form distorted CoDy2P4 tetrahedra that share corners with four equivalent Co(4)Dy2P4 tetrahedra, corners with four equivalent Co(2)Dy3P4 tetrahedra, corners with four equivalent Co(3)Dy3P4 tetrahedra, edges with two equivalent Co(3)Dy3P4 tetrahedra, and faces with four equivalent Co(2)Dy3P4 tetrahedra. Both Co(4)-P(2) bond lengths are 2.18 Å. Both Co(4)-P(3) bond lengths are 2.22 Å. In the fifth Co site, Co(5) is bonded in a distorted trigonal planar geometry to six equivalent Dy(2) and three equivalent P(3) atoms. All Co(5)-P(3) bond lengths are 2.16 Å. There are three inequivalent P sites. In the first P site, P(3) is bonded in a 9-coordinate geometry to four equivalent Dy(2), one Co(5), two equivalent Co(2), and two equivalent Co(4) atoms. In the second P site, P(1) is bonded in a 9-coordinate geometry to two equivalent Dy(2), one Co(1), two equivalent Co(2), and four equivalent Co(3) atoms. In the third P site, P(2) is bonded in a 9-coordinate geometry to two equivalent Dy(1), one Co(4), two equivalent Co(1), two equivalent Co(2), and two equivalent Co(3) atoms.