Yb5Pt9 crystallizes in the tetragonal P4_2/mnm space group. There are two inequivalent Yb sites. In the first Yb site, Yb(1) is bonded in a 9-coordinate geometry to one Pt(3), four equivalent Pt(1), and four equivalent Pt(2) atoms. In the second Yb site, Yb(2) is bonded in a distorted q6 geometry to two equivalent Pt(3), four equivalent Pt(1), and four equivalent Pt(2) atoms. There are three inequivalent Pt sites. In the first Pt site, Pt(1) is bonded to one Yb(2) and four equivalent Yb(1) atoms to form distorted PtYb5 cuboctahedra that share corners with ten equivalent Pt(1)Yb5 cuboctahedra,  a cornercorner with one Pt(3)Yb6 octahedra,  an edgeedge with one Pt(1)Yb5 cuboctahedra,  an edgeedge with one Pt(3)Yb6 octahedra,  a faceface with one Pt(1)Yb5 cuboctahedra, and  a faceface with one Pt(3)Yb6 octahedra. The corner-sharing octahedral tilt angles are 61°. In the second Pt site, Pt(2) is bonded in a 5-coordinate geometry to one Yb(2) and four equivalent Yb(1) atoms. In the third Pt site, Pt(3) is bonded to two equivalent Yb(2) and four equivalent Yb(1) atoms to form distorted PtYb6 octahedra that share corners with four equivalent Pt(1)Yb5 cuboctahedra, corners with two equivalent Pt(3)Yb6 octahedra, edges with four equivalent Pt(1)Yb5 cuboctahedra, and faces with four equivalent Pt(1)Yb5 cuboctahedra. The corner-sharing octahedra are not tilted.
Yb5Pt9 crystallizes in the tetragonal P4_2/mnm space group. There are two inequivalent Yb sites. In the first Yb site, Yb(1) is bonded in a 9-coordinate geometry to one Pt(3), four equivalent Pt(1), and four equivalent Pt(2) atoms. The Yb(1)-Pt(3) bond length is 3.06 Å. All Yb(1)-Pt(1) bond lengths are 2.94 Å. There are a spread of Yb(1)-Pt(2) bond distances ranging from 2.87-2.98 Å. In the second Yb site, Yb(2) is bonded in a distorted q6 geometry to two equivalent Pt(3), four equivalent Pt(1), and four equivalent Pt(2) atoms. Both Yb(2)-Pt(3) bond lengths are 2.84 Å. All Yb(2)-Pt(1) bond lengths are 2.97 Å. All Yb(2)-Pt(2) bond lengths are 2.74 Å. There are three inequivalent Pt sites. In the first Pt site, Pt(1) is bonded to one Yb(2) and four equivalent Yb(1) atoms to form distorted PtYb5 cuboctahedra that share corners with ten equivalent Pt(1)Yb5 cuboctahedra,  a cornercorner with one Pt(3)Yb6 octahedra,  an edgeedge with one Pt(1)Yb5 cuboctahedra,  an edgeedge with one Pt(3)Yb6 octahedra,  a faceface with one Pt(1)Yb5 cuboctahedra, and  a faceface with one Pt(3)Yb6 octahedra. The corner-sharing octahedral tilt angles are 61°. In the second Pt site, Pt(2) is bonded in a 5-coordinate geometry to one Yb(2) and four equivalent Yb(1) atoms. In the third Pt site, Pt(3) is bonded to two equivalent Yb(2) and four equivalent Yb(1) atoms to form distorted PtYb6 octahedra that share corners with four equivalent Pt(1)Yb5 cuboctahedra, corners with two equivalent Pt(3)Yb6 octahedra, edges with four equivalent Pt(1)Yb5 cuboctahedra, and faces with four equivalent Pt(1)Yb5 cuboctahedra. The corner-sharing octahedra are not tilted.