Materials Data on NpAl4 by Materials Project
NpAl4 crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. Np is bonded in a 11-coordinate geometry to thirteen Al atoms. There are a spread of Np–Al bond distances ranging from 3.03–3.13 Å. There are three inequivalent Al sites. In the first Al site, Al is bonded in a 10-coordinate geometry to three equivalent Np and seven Al atoms. There are a spread of Al–Al bond distances ranging from 2.62–2.95 Å. In the second Al site, Al is bonded to four equivalent Np and eight Al atoms to form a mixture of distorted face, edge, and corner-sharing AlNp4Al8 cuboctahedra. There are two shorter (3.07 Å) and four longer (3.12 Å) Al–Al bond lengths. In the third Al site, Al is bonded in a 3-coordinate geometry to three equivalent Np and ten Al atoms.