Materials Data on La2Al7Cu by Materials Project
La2CuAl7 crystallizes in the tetragonal P4mm space group. The structure is three-dimensional. there are two inequivalent La sites. In the first La site, La is bonded in a 8-coordinate geometry to four equivalent Cu and twelve Al atoms. All La–Cu bond lengths are 3.34 Å. There are a spread of La–Al bond distances ranging from 3.25–3.46 Å. In the second La site, La is bonded in a 8-coordinate geometry to sixteen Al atoms. There are a spread of La–Al bond distances ranging from 3.31–3.57 Å. Cu is bonded in a 9-coordinate geometry to four equivalent La and five Al atoms. There are one shorter (2.44 Å) and four longer (2.53 Å) Cu–Al bond lengths. There are five inequivalent Al sites. In the first Al site, Al is bonded in a distorted bent 120 degrees geometry to four La, two equivalent Cu, and two equivalent Al atoms. Both Al–Al bond lengths are 2.67 Å. In the second Al site, Al is bonded to four La and eight Al atoms to form a mixture of distorted face and corner-sharing AlLa4Al8 cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.65–3.06 Å. In the third Al site, Al is bonded in a 9-coordinate geometry to four equivalent La and five Al atoms. The Al–Al bond length is 2.56 Å. In the fourth Al site, Al is bonded in a 9-coordinate geometry to four equivalent La and five Al atoms. In the fifth Al site, Al is bonded in a distorted single-bond geometry to four equivalent La, one Cu, and four equivalent Al atoms.