Materials Data on NpPa3 by Materials Project
NpPa3 is Uranium Silicide-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Np is bonded to twelve Pa atoms to form NpPa12 cuboctahedra that share corners with four equivalent NpPa12 cuboctahedra, corners with eight equivalent PaNp4Pa8 cuboctahedra, edges with eight equivalent NpPa12 cuboctahedra, edges with sixteen equivalent PaNp4Pa8 cuboctahedra, faces with four equivalent NpPa12 cuboctahedra, and faces with fourteen PaNp4Pa8 cuboctahedra. There are four shorter (3.06 Å) and eight longer (3.29 Å) Np–Pa bond lengths. There are two inequivalent Pa sites. In the first Pa site, Pa is bonded to four equivalent Np and eight Pa atoms to form PaNp4Pa8 cuboctahedra that share corners with twelve equivalent PaNp4Pa8 cuboctahedra, edges with eight equivalent NpPa12 cuboctahedra, edges with sixteen PaNp4Pa8 cuboctahedra, faces with four equivalent NpPa12 cuboctahedra, and faces with fourteen PaNp4Pa8 cuboctahedra. There are four shorter (3.06 Å) and four longer (3.29 Å) Pa–Pa bond lengths. In the second Pa site, Pa is bonded to four equivalent Np and eight equivalent Pa atoms to form distorted PaNp4Pa8 cuboctahedra that share corners with four equivalent PaNp4Pa8 cuboctahedra, corners with eight equivalent NpPa12 cuboctahedra, edges with twenty-four PaNp4Pa8 cuboctahedra, faces with six equivalent NpPa12 cuboctahedra, and faces with twelve PaNp4Pa8 cuboctahedra.