Materials Data on Np3As by Materials Project
Np3As is Uranium Silicide-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Np sites. In the first Np site, Np is bonded to four equivalent Np and four equivalent As atoms to form distorted NpNp4As4 cuboctahedra that share corners with eight equivalent AsNp12 cuboctahedra, corners with sixteen NpNp4As4 cuboctahedra, edges with four equivalent AsNp12 cuboctahedra, edges with sixteen NpNp4As4 cuboctahedra, and faces with six equivalent NpNp4As4 cuboctahedra. All Np–Np bond lengths are 2.99 Å. All Np–As bond lengths are 2.99 Å. In the second Np site, Np is bonded to eight equivalent Np and four equivalent As atoms to form distorted NpNp8As4 cuboctahedra that share corners with eight equivalent AsNp12 cuboctahedra, corners with twenty NpNp4As4 cuboctahedra, edges with sixteen NpNp4As4 cuboctahedra, faces with four equivalent NpNp8As4 cuboctahedra, and faces with six equivalent AsNp12 cuboctahedra. All Np–As bond lengths are 3.02 Å. As is bonded to twelve Np atoms to form AsNp12 cuboctahedra that share corners with four equivalent AsNp12 cuboctahedra, corners with twenty-four NpNp4As4 cuboctahedra, edges with eight equivalent NpNp4As4 cuboctahedra, edges with eight equivalent AsNp12 cuboctahedra, faces with four equivalent AsNp12 cuboctahedra, and faces with six equivalent NpNp8As4 cuboctahedra.