Materials Data on BaAc3 by Materials Project
BaAc3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Ba is bonded to twelve Ac atoms to form BaAc12 cuboctahedra that share corners with six equivalent BaAc12 cuboctahedra, corners with twelve AcBa4Ac8 cuboctahedra, edges with eighteen AcBa4Ac8 cuboctahedra, faces with eight equivalent BaAc12 cuboctahedra, and faces with twelve AcBa4Ac8 cuboctahedra. There are six shorter (4.10 Å) and six longer (4.12 Å) Ba–Ac bond lengths. There are two inequivalent Ac sites. In the first Ac site, Ac is bonded to four equivalent Ba and eight Ac atoms to form AcBa4Ac8 cuboctahedra that share corners with four equivalent BaAc12 cuboctahedra, corners with fourteen AcBa4Ac8 cuboctahedra, edges with six equivalent BaAc12 cuboctahedra, edges with twelve AcBa4Ac8 cuboctahedra, faces with four equivalent BaAc12 cuboctahedra, and faces with sixteen AcBa4Ac8 cuboctahedra. There are a spread of Ac–Ac bond distances ranging from 4.00–4.24 Å. In the second Ac site, Ac is bonded to four equivalent Ba and eight equivalent Ac atoms to form AcBa4Ac8 cuboctahedra that share corners with four equivalent BaAc12 cuboctahedra, corners with fourteen AcBa4Ac8 cuboctahedra, edges with six equivalent BaAc12 cuboctahedra, edges with twelve equivalent AcBa4Ac8 cuboctahedra, faces with four equivalent BaAc12 cuboctahedra, and faces with sixteen AcBa4Ac8 cuboctahedra.