TaOs3 is beta-derived structured and crystallizes in the hexagonal P-6m2 space group. Ta(1) is bonded to six equivalent Ta(1) and six equivalent Os(2) atoms to form TaTa6Os6 cuboctahedra that share corners with six equivalent Ta(1)Ta6Os6 cuboctahedra, corners with twelve equivalent Os(1)Os12 cuboctahedra, edges with six equivalent Ta(1)Ta6Os6 cuboctahedra, edges with twelve equivalent Os(2)Ta3Os9 cuboctahedra, faces with two equivalent Os(1)Os12 cuboctahedra, faces with six equivalent Ta(1)Ta6Os6 cuboctahedra, and faces with twelve equivalent Os(2)Ta3Os9 cuboctahedra. There are two inequivalent Os sites. In the first Os site, Os(1) is bonded to six equivalent Os(1) and six equivalent Os(2) atoms to form OsOs12 cuboctahedra that share corners with six equivalent Os(1)Os12 cuboctahedra, corners with twelve equivalent Ta(1)Ta6Os6 cuboctahedra, edges with six equivalent Os(1)Os12 cuboctahedra, edges with twelve equivalent Os(2)Ta3Os9 cuboctahedra, faces with two equivalent Ta(1)Ta6Os6 cuboctahedra, faces with six equivalent Os(1)Os12 cuboctahedra, and faces with twelve equivalent Os(2)Ta3Os9 cuboctahedra. In the second Os site, Os(2) is bonded to three equivalent Ta(1), three equivalent Os(1), and six equivalent Os(2) atoms to form distorted OsTa3Os9 cuboctahedra that share corners with eighteen equivalent Os(2)Ta3Os9 cuboctahedra, edges with six equivalent Ta(1)Ta6Os6 cuboctahedra, edges with six equivalent Os(1)Os12 cuboctahedra, edges with six equivalent Os(2)Ta3Os9 cuboctahedra, faces with six equivalent Ta(1)Ta6Os6 cuboctahedra, faces with six equivalent Os(1)Os12 cuboctahedra, and faces with eight equivalent Os(2)Ta3Os9 cuboctahedra.
TaOs3 is beta-derived structured and crystallizes in the hexagonal P-6m2 space group. Ta(1) is bonded to six equivalent Ta(1) and six equivalent Os(2) atoms to form TaTa6Os6 cuboctahedra that share corners with six equivalent Ta(1)Ta6Os6 cuboctahedra, corners with twelve equivalent Os(1)Os12 cuboctahedra, edges with six equivalent Ta(1)Ta6Os6 cuboctahedra, edges with twelve equivalent Os(2)Ta3Os9 cuboctahedra, faces with two equivalent Os(1)Os12 cuboctahedra, faces with six equivalent Ta(1)Ta6Os6 cuboctahedra, and faces with twelve equivalent Os(2)Ta3Os9 cuboctahedra. All Ta(1)-Ta(1) bond lengths are 2.79 Å. All Ta(1)-Os(2) bond lengths are 2.89 Å. There are two inequivalent Os sites. In the first Os site, Os(1) is bonded to six equivalent Os(1) and six equivalent Os(2) atoms to form OsOs12 cuboctahedra that share corners with six equivalent Os(1)Os12 cuboctahedra, corners with twelve equivalent Ta(1)Ta6Os6 cuboctahedra, edges with six equivalent Os(1)Os12 cuboctahedra, edges with twelve equivalent Os(2)Ta3Os9 cuboctahedra, faces with two equivalent Ta(1)Ta6Os6 cuboctahedra, faces with six equivalent Os(1)Os12 cuboctahedra, and faces with twelve equivalent Os(2)Ta3Os9 cuboctahedra. All Os(1)-Os(1) bond lengths are 2.79 Å. All Os(1)-Os(2) bond lengths are 2.68 Å. In the second Os site, Os(2) is bonded to three equivalent Ta(1), three equivalent Os(1), and six equivalent Os(2) atoms to form distorted OsTa3Os9 cuboctahedra that share corners with eighteen equivalent Os(2)Ta3Os9 cuboctahedra, edges with six equivalent Ta(1)Ta6Os6 cuboctahedra, edges with six equivalent Os(1)Os12 cuboctahedra, edges with six equivalent Os(2)Ta3Os9 cuboctahedra, faces with six equivalent Ta(1)Ta6Os6 cuboctahedra, faces with six equivalent Os(1)Os12 cuboctahedra, and faces with eight equivalent Os(2)Ta3Os9 cuboctahedra. All Os(2)-Os(2) bond lengths are 2.79 Å.