Materials Data on K3Ge17 by Materials Project
KK2Ge17 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional and consists of eight potassium molecules and one K2Ge17 framework. In the K2Ge17 framework, K is bonded in a 8-coordinate geometry to twenty Ge atoms. There are a spread of K–Ge bond distances ranging from 3.46–3.68 Å. There are three inequivalent Ge sites. In the first Ge site, Ge is bonded in a body-centered cubic geometry to four equivalent K and four equivalent Ge atoms. All Ge–Ge bond lengths are 2.62 Å. In the second Ge site, Ge is bonded in a 7-coordinate geometry to three equivalent K and four Ge atoms. All Ge–Ge bond lengths are 2.59 Å. In the third Ge site, Ge is bonded in a 6-coordinate geometry to two equivalent K and four Ge atoms. There are two shorter (2.55 Å) and one longer (2.60 Å) Ge–Ge bond lengths.