Y2PdSi3 crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to four equivalent Pd(1) and eight equivalent Si(1) atoms to form distorted YSi8Pd4 cuboctahedra that share edges with four equivalent Y(2)Si12 cuboctahedra, edges with eight equivalent Y(1)Si8Pd4 cuboctahedra, faces with two equivalent Y(2)Si12 cuboctahedra, and faces with six equivalent Y(1)Si8Pd4 cuboctahedra. In the second Y site, Y(2) is bonded to twelve equivalent Si(1) atoms to form YSi12 cuboctahedra that share edges with twelve equivalent Y(1)Si8Pd4 cuboctahedra, faces with two equivalent Y(2)Si12 cuboctahedra, and faces with six equivalent Y(1)Si8Pd4 cuboctahedra. Pd(1) is bonded in a 9-coordinate geometry to six equivalent Y(1) and three equivalent Si(1) atoms. Si(1) is bonded in a 9-coordinate geometry to two equivalent Y(2), four equivalent Y(1), one Pd(1), and two equivalent Si(1) atoms.
Y2PdSi3 crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to four equivalent Pd(1) and eight equivalent Si(1) atoms to form distorted YSi8Pd4 cuboctahedra that share edges with four equivalent Y(2)Si12 cuboctahedra, edges with eight equivalent Y(1)Si8Pd4 cuboctahedra, faces with two equivalent Y(2)Si12 cuboctahedra, and faces with six equivalent Y(1)Si8Pd4 cuboctahedra. There are two shorter (3.03 Å) and two longer (3.20 Å) Y(1)-Pd(1) bond lengths. There are four shorter (3.05 Å) and four longer (3.15 Å) Y(1)-Si(1) bond lengths. In the second Y site, Y(2) is bonded to twelve equivalent Si(1) atoms to form YSi12 cuboctahedra that share edges with twelve equivalent Y(1)Si8Pd4 cuboctahedra, faces with two equivalent Y(2)Si12 cuboctahedra, and faces with six equivalent Y(1)Si8Pd4 cuboctahedra. There are six shorter (3.07 Å) and six longer (3.09 Å) Y(2)-Si(1) bond lengths. Pd(1) is bonded in a 9-coordinate geometry to six equivalent Y(1) and three equivalent Si(1) atoms. All Pd(1)-Si(1) bond lengths are 2.41 Å. Si(1) is bonded in a 9-coordinate geometry to two equivalent Y(2), four equivalent Y(1), one Pd(1), and two equivalent Si(1) atoms. Both Si(1)-Si(1) bond lengths are 2.36 Å.