Materials Data on Sr2Al7Ge by Materials Project
Sr2Al7Ge crystallizes in the tetragonal P4mm space group. The structure is three-dimensional. there are two inequivalent Sr sites. In the first Sr site, Sr is bonded in a 8-coordinate geometry to twelve Al and four equivalent Ge atoms. There are a spread of Sr–Al bond distances ranging from 3.42–3.57 Å. All Sr–Ge bond lengths are 3.42 Å. In the second Sr site, Sr is bonded in a 8-coordinate geometry to sixteen Al atoms. There are a spread of Sr–Al bond distances ranging from 3.42–3.57 Å. There are five inequivalent Al sites. In the first Al site, Al is bonded in a 2-coordinate geometry to four Sr, two equivalent Al, and two equivalent Ge atoms. Both Al–Al bond lengths are 2.66 Å. Both Al–Ge bond lengths are 2.68 Å. In the second Al site, Al is bonded in a 12-coordinate geometry to four Sr and four Al atoms. All Al–Al bond lengths are 2.67 Å. In the third Al site, Al is bonded in a 9-coordinate geometry to four equivalent Sr and five Al atoms. The Al–Al bond length is 2.63 Å. In the fourth Al site, Al is bonded in a 9-coordinate geometry to four equivalent Sr and five Al atoms. In the fifth Al site, Al is bonded in a distorted single-bond geometry to four equivalent Sr, four equivalent Al, and one Ge atom. The Al–Ge bond length is 2.61 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Sr and five Al atoms.