Materials Data on Ba7Al13 by Materials Project
Ba7Al13 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. there are four inequivalent Ba sites. In the first Ba site, Ba is bonded in a 12-coordinate geometry to twelve Al atoms. There are three shorter (3.53 Å) and nine longer (3.54 Å) Ba–Al bond lengths. In the second Ba site, Ba is bonded in a 4-coordinate geometry to ten Al atoms. There are three shorter (3.50 Å) and seven longer (3.56 Å) Ba–Al bond lengths. In the third Ba site, Ba is bonded in a 12-coordinate geometry to twelve Al atoms. There are a spread of Ba–Al bond distances ranging from 3.50–3.59 Å. In the fourth Ba site, Ba is bonded in a 6-coordinate geometry to six equivalent Al atoms. All Ba–Al bond lengths are 3.89 Å. There are four inequivalent Al sites. In the first Al site, Al is bonded to six Ba and six Al atoms to form a mixture of distorted corner, edge, and face-sharing AlBa6Al6 cuboctahedra. There are four shorter (3.03 Å) and two longer (3.16 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a 9-coordinate geometry to five Ba and four Al atoms. There are a spread of Al–Al bond distances ranging from 2.72–2.92 Å. In the third Al site, Al is bonded in a 9-coordinate geometry to six Ba and six Al atoms. In the fourth Al site, Al is bonded in a 10-coordinate geometry to seven Ba and three equivalent Al atoms.