UY4Pd15 is Uranium Silicide-derived structured and crystallizes in the tetragonal P4/mmm space group. U(1) is bonded to four equivalent Pd(1) and eight equivalent Pd(4) atoms to form UPd12 cuboctahedra that share corners with four equivalent U(1)Pd12 cuboctahedra, corners with eight equivalent Y(1)Pd12 cuboctahedra, faces with two equivalent Y(1)Pd12 cuboctahedra, faces with four equivalent U(1)Pd12 cuboctahedra, and faces with four equivalent Pd(1)U4Pd8 cuboctahedra. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to four equivalent Pd(2), four equivalent Pd(4), and four equivalent Pd(5) atoms to form YPd12 cuboctahedra that share corners with four equivalent U(1)Pd12 cuboctahedra, corners with four equivalent Y(1)Pd12 cuboctahedra, corners with four equivalent Y(2)Pd12 cuboctahedra, edges with four equivalent Pd(1)U4Pd8 cuboctahedra,  a faceface with one U(1)Pd12 cuboctahedra,  a faceface with one Y(2)Pd12 cuboctahedra, and faces with four equivalent Y(1)Pd12 cuboctahedra. In the second Y site, Y(2) is bonded to four equivalent Pd(3), four equivalent Pd(5), and four equivalent Pd(6) atoms to form a mixture of corner and face-sharing YPd12 cuboctahedra. There are six inequivalent Pd sites. In the first Pd site, Pd(1) is bonded to four equivalent U(1) and eight equivalent Pd(4) atoms to form distorted PdU4Pd8 cuboctahedra that share corners with four equivalent Pd(1)U4Pd8 cuboctahedra, edges with eight equivalent Y(1)Pd12 cuboctahedra, faces with four equivalent U(1)Pd12 cuboctahedra, and faces with four equivalent Pd(1)U4Pd8 cuboctahedra. In the second Pd site, Pd(2) is bonded in a distorted rectangular see-saw-like geometry to four equivalent Y(1) atoms. In the third Pd site, Pd(3) is bonded in a distorted rectangular see-saw-like geometry to four equivalent Y(2) atoms. In the fourth Pd site, Pd(4) is bonded in a distorted rectangular see-saw-like geometry to two equivalent U(1), two equivalent Y(1), and two equivalent Pd(1) atoms. In the fifth Pd site, Pd(5) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Y(1) and two equivalent Y(2) atoms. In the sixth Pd site, Pd(6) is bonded in a distorted square co-planar geometry to four equivalent Y(2) atoms.
UY4Pd15 is Uranium Silicide-derived structured and crystallizes in the tetragonal P4/mmm space group. U(1) is bonded to four equivalent Pd(1) and eight equivalent Pd(4) atoms to form UPd12 cuboctahedra that share corners with four equivalent U(1)Pd12 cuboctahedra, corners with eight equivalent Y(1)Pd12 cuboctahedra, faces with two equivalent Y(1)Pd12 cuboctahedra, faces with four equivalent U(1)Pd12 cuboctahedra, and faces with four equivalent Pd(1)U4Pd8 cuboctahedra. All U(1)-Pd(1) bond lengths are 2.91 Å. All U(1)-Pd(4) bond lengths are 2.88 Å. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to four equivalent Pd(2), four equivalent Pd(4), and four equivalent Pd(5) atoms to form YPd12 cuboctahedra that share corners with four equivalent U(1)Pd12 cuboctahedra, corners with four equivalent Y(1)Pd12 cuboctahedra, corners with four equivalent Y(2)Pd12 cuboctahedra, edges with four equivalent Pd(1)U4Pd8 cuboctahedra,  a faceface with one U(1)Pd12 cuboctahedra,  a faceface with one Y(2)Pd12 cuboctahedra, and faces with four equivalent Y(1)Pd12 cuboctahedra. All Y(1)-Pd(2) bond lengths are 2.91 Å. All Y(1)-Pd(4) bond lengths are 2.95 Å. All Y(1)-Pd(5) bond lengths are 2.87 Å. In the second Y site, Y(2) is bonded to four equivalent Pd(3), four equivalent Pd(5), and four equivalent Pd(6) atoms to form a mixture of corner and face-sharing YPd12 cuboctahedra. All Y(2)-Pd(3) bond lengths are 2.91 Å. All Y(2)-Pd(5) bond lengths are 2.91 Å. All Y(2)-Pd(6) bond lengths are 2.89 Å. There are six inequivalent Pd sites. In the first Pd site, Pd(1) is bonded to four equivalent U(1) and eight equivalent Pd(4) atoms to form distorted PdU4Pd8 cuboctahedra that share corners with four equivalent Pd(1)U4Pd8 cuboctahedra, edges with eight equivalent Y(1)Pd12 cuboctahedra, faces with four equivalent U(1)Pd12 cuboctahedra, and faces with four equivalent Pd(1)U4Pd8 cuboctahedra. All Pd(1)-Pd(4) bond lengths are 2.88 Å. In the second Pd site, Pd(2) is bonded in a distorted rectangular see-saw-like geometry to four equivalent Y(1) atoms. In the third Pd site, Pd(3) is bonded in a distorted rectangular see-saw-like geometry to four equivalent Y(2) atoms. In the fourth Pd site, Pd(4) is bonded in a distorted rectangular see-saw-like geometry to two equivalent U(1), two equivalent Y(1), and two equivalent Pd(1) atoms. In the fifth Pd site, Pd(5) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Y(1) and two equivalent Y(2) atoms. In the sixth Pd site, Pd(6) is bonded in a distorted square co-planar geometry to four equivalent Y(2) atoms.