Materials Data on Sr11(Ge2N3)2 by Materials Project

Abstract

Sr11Ge4N6 crystallizes in the tetragonal P4/nbm space group. The structure is three-dimensional. there are four inequivalent Sr sites. In the first Sr site, Sr is bonded in a 1-coordinate geometry to two equivalent Ge and three equivalent N atoms. Both Sr–Ge bond lengths are 3.29 Å. There are one shorter (2.47 Å) and two longer (2.82 Å) Sr–N bond lengths. In the second Sr site, Sr is bonded in a 2-coordinate geometry to two equivalent Ge and two equivalent N atoms. There are one shorter (3.35 Å) and one longer (3.79 Å) Sr–Ge bond lengths. Both Sr–N bond lengths are 2.62 Å. In the third Sr site, Sr is bonded in a 5-coordinate geometry to five N atoms. There are one shorter (2.45 Å) and four longer (2.93 Å) Sr–N bond lengths. In the fourth Sr site, Sr is bonded in a linear geometry to four equivalent Ge and two equivalent N atoms. All Sr–Ge bond lengths are 3.66 Å. Both Sr–N bond lengths are 2.71 Å. There are three inequivalent Ge sites. In the first Ge site, Ge is bonded in a water-like geometry to two equivalent N atoms. Both Ge–N bond lengths are 1.86 Å. In the second Ge site, Ge is bonded to twelve Sr atoms to form distorted GeSr12 cuboctahedra that share corners with four equivalent GeSr12 cuboctahedra, faces with four equivalent GeSr12 cuboctahedra, and faces with eight equivalent NSr6 octahedra. In the third Ge site, Ge is bonded in a 8-coordinate geometry to eight equivalent Sr atoms. There are two inequivalent N sites. In the first N site, N is bonded to five Sr and one Ge atom to form a mixture of distorted edge, face, and corner-sharing NSr5Ge octahedra. The corner-sharing octahedra tilt angles range from 32–74°. In the second N site, N is bonded to six Sr atoms to form NSr6 octahedra that share corners with nine NSr5Ge octahedra and faces with four equivalent GeSr12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–74°.