Materials Data on Sr7Cu44As23 by Materials Project
Sr7Cu44As23 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight As+2.65- atoms. There are four shorter (3.21 Å) and four longer (3.45 Å) Sr–As bond lengths. In the second Sr2+ site, Sr2+ is bonded in a body-centered cubic geometry to eight equivalent As+2.65- atoms. All Sr–As bond lengths are 3.22 Å. There are three inequivalent Cu+1.07+ sites. In the first Cu+1.07+ site, Cu+1.07+ is bonded to four As+2.65- atoms to form a mixture of corner and edge-sharing CuAs4 tetrahedra. There are three shorter (2.48 Å) and one longer (2.56 Å) Cu–As bond lengths. In the second Cu+1.07+ site, Cu+1.07+ is bonded to four As+2.65- atoms to form a mixture of corner and edge-sharing CuAs4 tetrahedra. There are two shorter (2.45 Å) and two longer (2.51 Å) Cu–As bond lengths. In the third Cu+1.07+ site, Cu+1.07+ is bonded to four As+2.65- atoms to form a mixture of distorted corner and edge-sharing CuAs4 tetrahedra. There are a spread of Cu–As bond distances ranging from 2.49–2.68 Å. There are four inequivalent As+2.65- sites. In the first As+2.65- site, As+2.65- is bonded in a cuboctahedral geometry to twelve equivalent Cu+1.07+ atoms. In the second As+2.65- site, As+2.65- is bonded in a body-centered cubic geometry to eight equivalent Cu+1.07+ atoms. In the third As+2.65- site, As+2.65- is bonded in a 10-coordinate geometry to two equivalent Sr2+ and eight Cu+1.07+ atoms. In the fourth As+2.65- site, As+2.65- is bonded in a 10-coordinate geometry to four Sr2+ and six Cu+1.07+ atoms.