Materials Data on Pr2Al7Cu by Materials Project
Pr2CuAl7 crystallizes in the tetragonal P4mm space group. The structure is three-dimensional. there are two inequivalent Pr sites. In the first Pr site, Pr is bonded in a 8-coordinate geometry to four equivalent Cu and twelve Al atoms. All Pr–Cu bond lengths are 3.31 Å. There are a spread of Pr–Al bond distances ranging from 3.20–3.43 Å. In the second Pr site, Pr is bonded in a 8-coordinate geometry to sixteen Al atoms. There are a spread of Pr–Al bond distances ranging from 3.27–3.57 Å. Cu is bonded in a 9-coordinate geometry to four equivalent Pr and five Al atoms. There are one shorter (2.41 Å) and four longer (2.50 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 Pr, 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 Pr and eight Al atoms to form a mixture of distorted face and corner-sharing AlPr4Al8 cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.64–3.02 Å. In the third Al site, Al is bonded in a 9-coordinate geometry to four equivalent Pr and five Al atoms. The Al–Al bond length is 2.54 Å. In the fourth Al site, Al is bonded in a 9-coordinate geometry to four equivalent Pr and five Al atoms. In the fifth Al site, Al is bonded in a distorted single-bond geometry to four equivalent Pr, one Cu, and four equivalent Al atoms.