Materials Data on Sr3(GeAs2)2 by Materials Project
Sr3(GeAs2)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to six As3- atoms to form a mixture of corner and edge-sharing SrAs6 octahedra. The corner-sharing octahedra tilt angles range from 3–10°. There are a spread of Sr–As bond distances ranging from 3.14–3.33 Å. In the second Sr2+ site, Sr2+ is bonded to six As3- atoms to form a mixture of corner and edge-sharing SrAs6 octahedra. The corner-sharing octahedra tilt angles range from 2–10°. There are a spread of Sr–As bond distances ranging from 3.15–3.26 Å. In the third Sr2+ site, Sr2+ is bonded to six As3- atoms to form a mixture of corner and edge-sharing SrAs6 octahedra. The corner-sharing octahedra tilt angles range from 2–7°. There are a spread of Sr–As bond distances ranging from 3.15–3.36 Å. There are two inequivalent Ge3+ sites. In the first Ge3+ site, Ge3+ is bonded in a trigonal non-coplanar geometry to three As3- atoms. There are a spread of Ge–As bond distances ranging from 2.45–2.54 Å. In the second Ge3+ site, Ge3+ is bonded in a trigonal non-coplanar geometry to three As3- atoms. There are one shorter (2.50 Å) and two longer (2.52 Å) Ge–As bond lengths. There are four inequivalent As3- sites. In the first As3- site, As3- is bonded to four Sr2+ and two equivalent Ge3+ atoms to form AsSr4Ge2 octahedra that share corners with eight AsSr5Ge octahedra and edges with eight AsSr4Ge2 octahedra. The corner-sharing octahedra tilt angles range from 3–93°. In the second As3- site, As3- is bonded to four Sr2+ and two Ge3+ atoms to form a mixture of corner and edge-sharing AsSr4Ge2 octahedra. The corner-sharing octahedra tilt angles range from 6–94°. In the third As3- site, As3- is bonded to five Sr2+ and one Ge3+ atom to form a mixture of corner and edge-sharing AsSr5Ge octahedra. The corner-sharing octahedra tilt angles range from 3–87°. In the fourth As3- site, As3- is bonded to five Sr2+ and one Ge3+ atom to form a mixture of corner and edge-sharing AsSr5Ge octahedra. The corner-sharing octahedra tilt angles range from 3–93°.