Materials Data on K7NaGe8 by Materials Project

K7NaGe8 crystallizes in the cubic Pa-3 space group. The structure is three-dimensional. there are two inequivalent K sites. In the first K site, K is bonded in a 6-coordinate geometry to six Ge atoms. There are a spread of K–Ge bond distances ranging from 3.41–3.68 Å. In the second K site, K is bonded in a distorted octahedral geometry to six equivalent Ge atoms. All K–Ge bond lengths are 3.96 Å. Na is bonded in a 6-coordinate geometry to six equivalent Ge atoms. All Na–Ge bond lengths are 2.95 Å. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to five K, one Na, and three Ge atoms. There are one shorter (2.57 Å) and two longer (2.66 Å) Ge–Ge bond lengths. In the second Ge site, Ge is bonded in a 9-coordinate geometry to six equivalent K and three equivalent Ge atoms.

K7NaGe8 属于立方晶系，空间群为Pa-3。该晶体结构为三维结构。体系中存在两个不等价的钾（K）位点。在第一个钾位点中，钾原子采用六配位几何构型，与六个锗（Ge）原子成键，K-Ge键的键长分布范围为3.41~3.68 埃。在第二个钾位点中，钾原子采用畸变八面体配位构型，与六个等价的锗原子成键，所有K-Ge键的键长均为3.96 埃。钠（Na）原子采用六配位几何构型，与六个等价的锗原子成键，所有Na-Ge键的键长均为2.95 埃。体系中存在两个不等价的锗位点。在第一个锗位点中，锗原子采用九配位几何构型，与五个钾原子、一个钠原子以及三个锗原子成键，Ge-Ge键存在1条较短键长（2.57 埃）与2条较长键长（2.66 埃）。在第二个锗位点中，锗原子采用九配位几何构型，与六个等价的钾原子以及三个等价的锗原子成键。