SmPr3 is alpha La-derived structured and crystallizes in the tetragonal I4/mmm space group. Sm(1) is bonded to four equivalent Pr(2) and eight equivalent Pr(1) atoms to form SmPr12 cuboctahedra that share corners with four equivalent Sm(1)Pr12 cuboctahedra, corners with eight equivalent Pr(2)Pr8Sm4 cuboctahedra, edges with eight equivalent Sm(1)Pr12 cuboctahedra, edges with sixteen equivalent Pr(1)Pr8Sm4 cuboctahedra, faces with four equivalent Sm(1)Pr12 cuboctahedra, faces with six equivalent Pr(2)Pr8Sm4 cuboctahedra, and faces with eight equivalent Pr(1)Pr8Sm4 cuboctahedra. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to four equivalent Sm(1), four equivalent Pr(1), and four equivalent Pr(2) atoms to form PrPr8Sm4 cuboctahedra that share corners with twelve equivalent Pr(1)Pr8Sm4 cuboctahedra, edges with eight equivalent Sm(1)Pr12 cuboctahedra, edges with eight equivalent Pr(1)Pr8Sm4 cuboctahedra, edges with eight equivalent Pr(2)Pr8Sm4 cuboctahedra, faces with four equivalent Sm(1)Pr12 cuboctahedra, faces with four equivalent Pr(2)Pr8Sm4 cuboctahedra, and faces with ten equivalent Pr(1)Pr8Sm4 cuboctahedra. In the second Pr site, Pr(2) is bonded to four equivalent Sm(1) and eight equivalent Pr(1) atoms to form PrPr8Sm4 cuboctahedra that share corners with four equivalent Pr(2)Pr8Sm4 cuboctahedra, corners with eight equivalent Sm(1)Pr12 cuboctahedra, edges with eight equivalent Pr(2)Pr8Sm4 cuboctahedra, edges with sixteen equivalent Pr(1)Pr8Sm4 cuboctahedra, faces with four equivalent Pr(2)Pr8Sm4 cuboctahedra, faces with six equivalent Sm(1)Pr12 cuboctahedra, and faces with eight equivalent Pr(1)Pr8Sm4 cuboctahedra.
SmPr3 is alpha La-derived structured and crystallizes in the tetragonal I4/mmm space group. Sm(1) is bonded to four equivalent Pr(2) and eight equivalent Pr(1) atoms to form SmPr12 cuboctahedra that share corners with four equivalent Sm(1)Pr12 cuboctahedra, corners with eight equivalent Pr(2)Pr8Sm4 cuboctahedra, edges with eight equivalent Sm(1)Pr12 cuboctahedra, edges with sixteen equivalent Pr(1)Pr8Sm4 cuboctahedra, faces with four equivalent Sm(1)Pr12 cuboctahedra, faces with six equivalent Pr(2)Pr8Sm4 cuboctahedra, and faces with eight equivalent Pr(1)Pr8Sm4 cuboctahedra. All Sm(1)-Pr(2) bond lengths are 3.71 Å. All Sm(1)-Pr(1) bond lengths are 3.70 Å. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to four equivalent Sm(1), four equivalent Pr(1), and four equivalent Pr(2) atoms to form PrPr8Sm4 cuboctahedra that share corners with twelve equivalent Pr(1)Pr8Sm4 cuboctahedra, edges with eight equivalent Sm(1)Pr12 cuboctahedra, edges with eight equivalent Pr(1)Pr8Sm4 cuboctahedra, edges with eight equivalent Pr(2)Pr8Sm4 cuboctahedra, faces with four equivalent Sm(1)Pr12 cuboctahedra, faces with four equivalent Pr(2)Pr8Sm4 cuboctahedra, and faces with ten equivalent Pr(1)Pr8Sm4 cuboctahedra. All Pr(1)-Pr(1) bond lengths are 3.71 Å. All Pr(1)-Pr(2) bond lengths are 3.70 Å. In the second Pr site, Pr(2) is bonded to four equivalent Sm(1) and eight equivalent Pr(1) atoms to form PrPr8Sm4 cuboctahedra that share corners with four equivalent Pr(2)Pr8Sm4 cuboctahedra, corners with eight equivalent Sm(1)Pr12 cuboctahedra, edges with eight equivalent Pr(2)Pr8Sm4 cuboctahedra, edges with sixteen equivalent Pr(1)Pr8Sm4 cuboctahedra, faces with four equivalent Pr(2)Pr8Sm4 cuboctahedra, faces with six equivalent Sm(1)Pr12 cuboctahedra, and faces with eight equivalent Pr(1)Pr8Sm4 cuboctahedra.