W3Os3C2 is H-Phase-like structured and crystallizes in the trigonal P-3m1 space group. There are two inequivalent W sites. In the first W site, W(1) is bonded to three equivalent W(2), six equivalent W(1), and three equivalent Os(1) atoms to form WOs3W9 cuboctahedra that share corners with nine equivalent W(1)Os3W9 cuboctahedra, corners with six equivalent C(1)Os6 octahedra, edges with six equivalent W(2)W12 cuboctahedra, edges with nine equivalent W(1)Os3W9 cuboctahedra, faces with six equivalent W(1)Os3W9 cuboctahedra, faces with six equivalent W(2)W12 cuboctahedra, and  a faceface with one C(1)Os6 octahedra. The corner-sharing octahedral tilt angles are 43°. In the second W site, W(2) is bonded to six equivalent W(1) and six equivalent W(2) atoms to form WW12 cuboctahedra that share corners with six equivalent W(2)W12 cuboctahedra, edges with six equivalent W(2)W12 cuboctahedra, edges with twelve equivalent W(1)Os3W9 cuboctahedra, faces with six equivalent W(2)W12 cuboctahedra, and faces with twelve equivalent W(1)Os3W9 cuboctahedra. There are two inequivalent Os sites. In the first Os site, Os(1) is bonded in a 3-coordinate geometry to three equivalent W(1) and three equivalent C(1) atoms. In the second Os site, Os(2) is bonded to six equivalent C(1) atoms to form distorted edge-sharing OsC6 octahedra. C(1) is bonded to three equivalent Os(1) and three equivalent Os(2) atoms to form COs6 octahedra that share corners with six equivalent W(1)Os3W9 cuboctahedra, corners with three equivalent C(1)Os6 octahedra, edges with nine equivalent C(1)Os6 octahedra, and  a faceface with one W(1)Os3W9 cuboctahedra. The corner-sharing octahedra are not tilted.
W3Os3C2 is H-Phase-like structured and crystallizes in the trigonal P-3m1 space group. There are two inequivalent W sites. In the first W site, W(1) is bonded to three equivalent W(2), six equivalent W(1), and three equivalent Os(1) atoms to form WOs3W9 cuboctahedra that share corners with nine equivalent W(1)Os3W9 cuboctahedra, corners with six equivalent C(1)Os6 octahedra, edges with six equivalent W(2)W12 cuboctahedra, edges with nine equivalent W(1)Os3W9 cuboctahedra, faces with six equivalent W(1)Os3W9 cuboctahedra, faces with six equivalent W(2)W12 cuboctahedra, and  a faceface with one C(1)Os6 octahedra. The corner-sharing octahedral tilt angles are 43°. All W(1)-W(2) bond lengths are 2.92 Å. All W(1)-W(1) bond lengths are 2.85 Å. All W(1)-Os(1) bond lengths are 2.75 Å. In the second W site, W(2) is bonded to six equivalent W(1) and six equivalent W(2) atoms to form WW12 cuboctahedra that share corners with six equivalent W(2)W12 cuboctahedra, edges with six equivalent W(2)W12 cuboctahedra, edges with twelve equivalent W(1)Os3W9 cuboctahedra, faces with six equivalent W(2)W12 cuboctahedra, and faces with twelve equivalent W(1)Os3W9 cuboctahedra. All W(2)-W(2) bond lengths are 2.85 Å. There are two inequivalent Os sites. In the first Os site, Os(1) is bonded in a 3-coordinate geometry to three equivalent W(1) and three equivalent C(1) atoms. All Os(1)-C(1) bond lengths are 2.12 Å. In the second Os site, Os(2) is bonded to six equivalent C(1) atoms to form distorted edge-sharing OsC6 octahedra. All Os(2)-C(1) bond lengths are 2.22 Å. C(1) is bonded to three equivalent Os(1) and three equivalent Os(2) atoms to form COs6 octahedra that share corners with six equivalent W(1)Os3W9 cuboctahedra, corners with three equivalent C(1)Os6 octahedra, edges with nine equivalent C(1)Os6 octahedra, and  a faceface with one W(1)Os3W9 cuboctahedra. The corner-sharing octahedra are not tilted.