Sm3Hf is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded to four equivalent Sm(1), four equivalent Sm(2), and four equivalent Hf(1) atoms to form SmSm8Hf4 cuboctahedra that share corners with twelve equivalent Sm(1)Sm8Hf4 cuboctahedra, edges with eight equivalent Sm(1)Sm8Hf4 cuboctahedra, edges with eight equivalent Sm(2)Sm8Hf4 cuboctahedra, edges with eight equivalent Hf(1)Sm12 cuboctahedra, faces with four equivalent Sm(2)Sm8Hf4 cuboctahedra, faces with four equivalent Hf(1)Sm12 cuboctahedra, and faces with ten equivalent Sm(1)Sm8Hf4 cuboctahedra. In the second Sm site, Sm(2) is bonded to eight equivalent Sm(1) and four equivalent Hf(1) atoms to form SmSm8Hf4 cuboctahedra that share corners with four equivalent Sm(2)Sm8Hf4 cuboctahedra, corners with eight equivalent Hf(1)Sm12 cuboctahedra, edges with eight equivalent Sm(2)Sm8Hf4 cuboctahedra, edges with sixteen equivalent Sm(1)Sm8Hf4 cuboctahedra, faces with four equivalent Sm(2)Sm8Hf4 cuboctahedra, faces with six equivalent Hf(1)Sm12 cuboctahedra, and faces with eight equivalent Sm(1)Sm8Hf4 cuboctahedra. Hf(1) is bonded to four equivalent Sm(2) and eight equivalent Sm(1) atoms to form HfSm12 cuboctahedra that share corners with four equivalent Hf(1)Sm12 cuboctahedra, corners with eight equivalent Sm(2)Sm8Hf4 cuboctahedra, edges with eight equivalent Hf(1)Sm12 cuboctahedra, edges with sixteen equivalent Sm(1)Sm8Hf4 cuboctahedra, faces with four equivalent Hf(1)Sm12 cuboctahedra, faces with six equivalent Sm(2)Sm8Hf4 cuboctahedra, and faces with eight equivalent Sm(1)Sm8Hf4 cuboctahedra.
Sm3Hf is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded to four equivalent Sm(1), four equivalent Sm(2), and four equivalent Hf(1) atoms to form SmSm8Hf4 cuboctahedra that share corners with twelve equivalent Sm(1)Sm8Hf4 cuboctahedra, edges with eight equivalent Sm(1)Sm8Hf4 cuboctahedra, edges with eight equivalent Sm(2)Sm8Hf4 cuboctahedra, edges with eight equivalent Hf(1)Sm12 cuboctahedra, faces with four equivalent Sm(2)Sm8Hf4 cuboctahedra, faces with four equivalent Hf(1)Sm12 cuboctahedra, and faces with ten equivalent Sm(1)Sm8Hf4 cuboctahedra. All Sm(1)-Sm(1) bond lengths are 3.50 Å. All Sm(1)-Sm(2) bond lengths are 3.48 Å. All Sm(1)-Hf(1) bond lengths are 3.48 Å. In the second Sm site, Sm(2) is bonded to eight equivalent Sm(1) and four equivalent Hf(1) atoms to form SmSm8Hf4 cuboctahedra that share corners with four equivalent Sm(2)Sm8Hf4 cuboctahedra, corners with eight equivalent Hf(1)Sm12 cuboctahedra, edges with eight equivalent Sm(2)Sm8Hf4 cuboctahedra, edges with sixteen equivalent Sm(1)Sm8Hf4 cuboctahedra, faces with four equivalent Sm(2)Sm8Hf4 cuboctahedra, faces with six equivalent Hf(1)Sm12 cuboctahedra, and faces with eight equivalent Sm(1)Sm8Hf4 cuboctahedra. All Sm(2)-Hf(1) bond lengths are 3.50 Å. Hf(1) is bonded to four equivalent Sm(2) and eight equivalent Sm(1) atoms to form HfSm12 cuboctahedra that share corners with four equivalent Hf(1)Sm12 cuboctahedra, corners with eight equivalent Sm(2)Sm8Hf4 cuboctahedra, edges with eight equivalent Hf(1)Sm12 cuboctahedra, edges with sixteen equivalent Sm(1)Sm8Hf4 cuboctahedra, faces with four equivalent Hf(1)Sm12 cuboctahedra, faces with six equivalent Sm(2)Sm8Hf4 cuboctahedra, and faces with eight equivalent Sm(1)Sm8Hf4 cuboctahedra.