DOE OSTI2020
Pa3Tl is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Pa sites. In the first Pa site, Pa is bonded to eight Pa and four equivalent Tl atoms to form PaPa8Tl4 cuboctahedra that share corners with twelve equivalent PaPa8Tl4 cuboctahedra, edges with eight equivalent TlPa12 cuboctahedra, edges with sixteen PaPa8Tl4 cuboctahedra, faces with four equivalent TlPa12 cuboctahedra, and faces with fourteen PaPa8Tl4 cuboctahedra. There are four shorter (3.29 Å) and four longer (3.30 Å) Pa–Pa bond lengths. All Pa–Tl bond lengths are 3.30 Å. In the second Pa site, Pa is bonded to eight equivalent Pa and four equivalent Tl atoms to form PaPa8Tl4 cuboctahedra that share corners with four equivalent PaPa8Tl4 cuboctahedra, corners with eight equivalent TlPa12 cuboctahedra, edges with twenty-four PaPa8Tl4 cuboctahedra, faces with six equivalent TlPa12 cuboctahedra, and faces with twelve PaPa8Tl4 cuboctahedra. All Pa–Tl bond lengths are 3.29 Å. Tl is bonded to twelve Pa atoms to form TlPa12 cuboctahedra that share corners with four equivalent TlPa12 cuboctahedra, corners with eight equivalent PaPa8Tl4 cuboctahedra, edges with eight equivalent TlPa12 cuboctahedra, edges with sixteen equivalent PaPa8Tl4 cuboctahedra, faces with four equivalent TlPa12 cuboctahedra, and faces with fourteen PaPa8Tl4 cuboctahedra.