Materials Data on Al4Cu9 by Materials Project
Al4Cu9 is gamma-brass-like structured and crystallizes in the cubic P-43m space group. The structure is three-dimensional. there are six inequivalent Cu sites. In the first Cu site, Cu is bonded in a 12-coordinate geometry to six Cu and six Al atoms. There are three shorter (2.51 Å) and three longer (2.64 Å) Cu–Cu bond lengths. There are three shorter (2.59 Å) and three longer (2.60 Å) Cu–Al bond lengths. In the second Cu site, Cu is bonded in a 12-coordinate geometry to nine Cu and three equivalent Al atoms. There are a spread of Cu–Cu bond distances ranging from 2.53–2.61 Å. All Cu–Al bond lengths are 2.58 Å. In the third Cu site, Cu is bonded in a distorted trigonal planar geometry to nine Cu and three equivalent Al atoms. There are three shorter (2.57 Å) and three longer (2.66 Å) Cu–Cu bond lengths. All Cu–Al bond lengths are 2.46 Å. In the fourth Cu site, Cu is bonded in a 4-coordinate geometry to seven Cu and six Al atoms. There are one shorter (2.51 Å) and four longer (2.79 Å) Cu–Cu bond lengths. There are four shorter (2.53 Å) and two longer (2.81 Å) Cu–Al bond lengths. In the fifth Cu site, Cu is bonded in a 9-coordinate geometry to nine Cu and four equivalent Al atoms. There are a spread of Cu–Cu bond distances ranging from 2.47–2.73 Å. All Cu–Al bond lengths are 2.74 Å. In the sixth Cu site, Cu is bonded in a 5-coordinate geometry to six Cu and five Al atoms. There are a spread of Cu–Al bond distances ranging from 2.53–2.60 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded in a 9-coordinate geometry to nine Cu atoms. In the second Al site, Al is bonded in a 11-coordinate geometry to eleven Cu atoms.