Hf3C is Uranium Silicide-like structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to four equivalent Hf(1), four equivalent Hf(2), and four equivalent C(1) atoms to form distorted HfHf8C4 cuboctahedra that share corners with twelve equivalent Hf(1)Hf8C4 cuboctahedra, edges with eight equivalent Hf(1)Hf8C4 cuboctahedra, edges with eight equivalent C(1)Hf12 cuboctahedra, faces with four equivalent C(1)Hf12 cuboctahedra, and faces with ten equivalent Hf(1)Hf8C4 cuboctahedra. In the second Hf site, Hf(2) is bonded in a square co-planar geometry to eight equivalent Hf(1) and four equivalent C(1) atoms. C(1) is bonded to four equivalent Hf(2) and eight equivalent Hf(1) atoms to form CHf12 cuboctahedra that share corners with four equivalent C(1)Hf12 cuboctahedra, edges with eight equivalent C(1)Hf12 cuboctahedra, edges with sixteen equivalent Hf(1)Hf8C4 cuboctahedra, faces with four equivalent C(1)Hf12 cuboctahedra, and faces with eight equivalent Hf(1)Hf8C4 cuboctahedra.
Hf3C is Uranium Silicide-like structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to four equivalent Hf(1), four equivalent Hf(2), and four equivalent C(1) atoms to form distorted HfHf8C4 cuboctahedra that share corners with twelve equivalent Hf(1)Hf8C4 cuboctahedra, edges with eight equivalent Hf(1)Hf8C4 cuboctahedra, edges with eight equivalent C(1)Hf12 cuboctahedra, faces with four equivalent C(1)Hf12 cuboctahedra, and faces with ten equivalent Hf(1)Hf8C4 cuboctahedra. All Hf(1)-Hf(1) bond lengths are 2.78 Å. All Hf(1)-Hf(2) bond lengths are 3.01 Å. All Hf(1)-C(1) bond lengths are 3.01 Å. In the second Hf site, Hf(2) is bonded in a square co-planar geometry to eight equivalent Hf(1) and four equivalent C(1) atoms. All Hf(2)-C(1) bond lengths are 2.78 Å. C(1) is bonded to four equivalent Hf(2) and eight equivalent Hf(1) atoms to form CHf12 cuboctahedra that share corners with four equivalent C(1)Hf12 cuboctahedra, edges with eight equivalent C(1)Hf12 cuboctahedra, edges with sixteen equivalent Hf(1)Hf8C4 cuboctahedra, faces with four equivalent C(1)Hf12 cuboctahedra, and faces with eight equivalent Hf(1)Hf8C4 cuboctahedra.