Materials Data on Ce3UAl8 by Materials Project
UCe3Al8 is Hexagonal Laves-derived structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. U is bonded in a 1-coordinate geometry to four Ce and twelve Al atoms. There are one shorter (3.31 Å) and three longer (3.38 Å) U–Ce bond lengths. All U–Al bond lengths are 3.26 Å. There are three inequivalent Ce sites. In the first Ce site, Ce is bonded in a 12-coordinate geometry to three equivalent Ce and twelve Al atoms. All Ce–Ce bond lengths are 3.44 Å. There are three shorter (3.26 Å) and nine longer (3.28 Å) Ce–Al bond lengths. In the second Ce site, Ce is bonded in a 9-coordinate geometry to one U, three equivalent Ce, and twelve Al atoms. There are a spread of Ce–Al bond distances ranging from 3.22–3.37 Å. In the third Ce site, Ce is bonded in a 12-coordinate geometry to three equivalent U and twelve Al atoms. There are a spread of Ce–Al bond distances ranging from 3.19–3.30 Å. There are four inequivalent Al sites. In the first Al site, Al is bonded to two equivalent U, four Ce, and six Al atoms to form a mixture of edge, corner, and face-sharing AlCe4U2Al6 cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.77–2.80 Å. In the second Al site, Al is bonded to one U, five Ce, and six Al atoms to form a mixture of edge, corner, and face-sharing AlCe5UAl6 cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.78–2.80 Å. In the third Al site, Al is bonded to three equivalent U, three equivalent Ce, and six Al atoms to form AlCe3U3Al6 cuboctahedra that share corners with eighteen AlCe4U2Al6 cuboctahedra, edges with six equivalent AlCe3U3Al6 cuboctahedra, and faces with eighteen AlCe4U2Al6 cuboctahedra. In the fourth Al site, Al is bonded to six Ce and six Al atoms to form AlCe6Al6 cuboctahedra that share corners with eighteen AlCe4U2Al6 cuboctahedra, edges with six equivalent AlCe6Al6 cuboctahedra, and faces with eighteen AlCe4U2Al6 cuboctahedra.