Sc2Mo4Al3C3 is H-Phase-derived structured and crystallizes in the orthorhombic Cmcm space group. Sc(1) is bonded in a 3-coordinate geometry to four equivalent Al(2), one C(2), and two equivalent C(1) atoms. Mo(1) is bonded in a 3-coordinate geometry to one Al(1), two equivalent Al(2), one C(2), and two equivalent C(1) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 4-coordinate geometry to four equivalent Mo(1) and four equivalent Al(2) atoms. In the second Al site, Al(2) is bonded in a 12-coordinate geometry to four equivalent Sc(1), four equivalent Mo(1), two equivalent Al(1), and two equivalent Al(2) atoms. There are two inequivalent C sites. In the first C site, C(1) is bonded to two equivalent Sc(1) and four equivalent Mo(1) atoms to form edge-sharing CSc2Mo4 octahedra. In the second C site, C(2) is bonded to two equivalent Sc(1) and four equivalent Mo(1) atoms to form edge-sharing CSc2Mo4 octahedra.
Sc2Mo4Al3C3 is H-Phase-derived structured and crystallizes in the orthorhombic Cmcm space group. Sc(1) is bonded in a 3-coordinate geometry to four equivalent Al(2), one C(2), and two equivalent C(1) atoms. There are two shorter (3.28 Å) and two longer (3.36 Å) Sc(1)-Al(2) bond lengths. The Sc(1)-C(2) bond length is 2.35 Å. Both Sc(1)-C(1) bond lengths are 2.34 Å. Mo(1) is bonded in a 3-coordinate geometry to one Al(1), two equivalent Al(2), one C(2), and two equivalent C(1) atoms. The Mo(1)-Al(1) bond length is 2.78 Å. There is one shorter (2.80 Å) and one longer (2.82 Å) Mo(1)-Al(2) bond length. The Mo(1)-C(2) bond length is 2.08 Å. There is one shorter (2.07 Å) and one longer (2.15 Å) Mo(1)-C(1) bond length. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 4-coordinate geometry to four equivalent Mo(1) and four equivalent Al(2) atoms. All Al(1)-Al(2) bond lengths are 2.72 Å. In the second Al site, Al(2) is bonded in a 12-coordinate geometry to four equivalent Sc(1), four equivalent Mo(1), two equivalent Al(1), and two equivalent Al(2) atoms. Both Al(2)-Al(2) bond lengths are 2.70 Å. There are two inequivalent C sites. In the first C site, C(1) is bonded to two equivalent Sc(1) and four equivalent Mo(1) atoms to form edge-sharing CSc2Mo4 octahedra. In the second C site, C(2) is bonded to two equivalent Sc(1) and four equivalent Mo(1) atoms to form edge-sharing CSc2Mo4 octahedra.