HoPr3 crystallizes in the tetragonal I4/mmm space group. Ho(1) is bonded to four equivalent Pr(2) and eight equivalent Pr(1) atoms to form HoPr12 cuboctahedra that share corners with four equivalent Ho(1)Pr12 cuboctahedra, corners with eight equivalent Pr(2)Pr8Ho4 cuboctahedra, edges with eight equivalent Ho(1)Pr12 cuboctahedra, edges with sixteen equivalent Pr(1)Pr8Ho4 cuboctahedra, faces with four equivalent Ho(1)Pr12 cuboctahedra, faces with six equivalent Pr(2)Pr8Ho4 cuboctahedra, and faces with eight equivalent Pr(1)Pr8Ho4 cuboctahedra. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to four equivalent Ho(1), four equivalent Pr(1), and four equivalent Pr(2) atoms to form PrPr8Ho4 cuboctahedra that share corners with twelve equivalent Pr(1)Pr8Ho4 cuboctahedra, edges with eight equivalent Ho(1)Pr12 cuboctahedra, edges with eight equivalent Pr(1)Pr8Ho4 cuboctahedra, edges with eight equivalent Pr(2)Pr8Ho4 cuboctahedra, faces with four equivalent Ho(1)Pr12 cuboctahedra, faces with four equivalent Pr(2)Pr8Ho4 cuboctahedra, and faces with ten equivalent Pr(1)Pr8Ho4 cuboctahedra. In the second Pr site, Pr(2) is bonded to four equivalent Ho(1) and eight equivalent Pr(1) atoms to form PrPr8Ho4 cuboctahedra that share corners with four equivalent Pr(2)Pr8Ho4 cuboctahedra, corners with eight equivalent Ho(1)Pr12 cuboctahedra, edges with eight equivalent Pr(2)Pr8Ho4 cuboctahedra, edges with sixteen equivalent Pr(1)Pr8Ho4 cuboctahedra, faces with four equivalent Pr(2)Pr8Ho4 cuboctahedra, faces with six equivalent Ho(1)Pr12 cuboctahedra, and faces with eight equivalent Pr(1)Pr8Ho4 cuboctahedra.
HoPr3 crystallizes in the tetragonal I4/mmm space group. Ho(1) is bonded to four equivalent Pr(2) and eight equivalent Pr(1) atoms to form HoPr12 cuboctahedra that share corners with four equivalent Ho(1)Pr12 cuboctahedra, corners with eight equivalent Pr(2)Pr8Ho4 cuboctahedra, edges with eight equivalent Ho(1)Pr12 cuboctahedra, edges with sixteen equivalent Pr(1)Pr8Ho4 cuboctahedra, faces with four equivalent Ho(1)Pr12 cuboctahedra, faces with six equivalent Pr(2)Pr8Ho4 cuboctahedra, and faces with eight equivalent Pr(1)Pr8Ho4 cuboctahedra. All Ho(1)-Pr(2) bond lengths are 3.68 Å. All Ho(1)-Pr(1) bond lengths are 3.67 Å. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to four equivalent Ho(1), four equivalent Pr(1), and four equivalent Pr(2) atoms to form PrPr8Ho4 cuboctahedra that share corners with twelve equivalent Pr(1)Pr8Ho4 cuboctahedra, edges with eight equivalent Ho(1)Pr12 cuboctahedra, edges with eight equivalent Pr(1)Pr8Ho4 cuboctahedra, edges with eight equivalent Pr(2)Pr8Ho4 cuboctahedra, faces with four equivalent Ho(1)Pr12 cuboctahedra, faces with four equivalent Pr(2)Pr8Ho4 cuboctahedra, and faces with ten equivalent Pr(1)Pr8Ho4 cuboctahedra. All Pr(1)-Pr(1) bond lengths are 3.68 Å. All Pr(1)-Pr(2) bond lengths are 3.67 Å. In the second Pr site, Pr(2) is bonded to four equivalent Ho(1) and eight equivalent Pr(1) atoms to form PrPr8Ho4 cuboctahedra that share corners with four equivalent Pr(2)Pr8Ho4 cuboctahedra, corners with eight equivalent Ho(1)Pr12 cuboctahedra, edges with eight equivalent Pr(2)Pr8Ho4 cuboctahedra, edges with sixteen equivalent Pr(1)Pr8Ho4 cuboctahedra, faces with four equivalent Pr(2)Pr8Ho4 cuboctahedra, faces with six equivalent Ho(1)Pr12 cuboctahedra, and faces with eight equivalent Pr(1)Pr8Ho4 cuboctahedra.