DOE OSTI2020
Sr2Zn5Si3 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 Zn and four equivalent Si atoms. There are a spread of Sr–Zn bond distances ranging from 3.27–3.49 Å. All Sr–Si bond lengths are 3.26 Å. In the second Sr site, Sr is bonded in a 8-coordinate geometry to eight Zn and eight Si atoms. There are four shorter (3.39 Å) and four longer (3.41 Å) Sr–Zn bond lengths. There are four shorter (3.25 Å) and four longer (3.26 Å) Sr–Si bond lengths. There are three inequivalent Zn sites. In the first Zn site, Zn is bonded in a 2-coordinate geometry to four Sr, two equivalent Zn, and two equivalent Si atoms. Both Zn–Zn bond lengths are 2.61 Å. Both Zn–Si bond lengths are 2.58 Å. In the second Zn site, Zn is bonded to four Sr and four Si atoms to form a mixture of distorted edge and face-sharing ZnSr4Si4 tetrahedra. All Zn–Si bond lengths are 2.57 Å. In the third Zn site, Zn is bonded in a distorted single-bond geometry to four equivalent Sr, four equivalent Zn, and one Si atom. The Zn–Si bond length is 2.48 Å. There are three inequivalent Si sites. In the first Si site, Si is bonded in a 9-coordinate geometry to four equivalent Sr, four equivalent Zn, and one Si atom. The Si–Si bond length is 2.41 Å. In the second Si site, Si is bonded in a 9-coordinate geometry to four equivalent Sr, four equivalent Zn, and one Si atom. In the third Si site, Si is bonded in a 9-coordinate geometry to four equivalent Sr and five Zn atoms.