Weippert Valentin, Chau Thanh, Witthaut Kristian, Johrendt Dirk
Department of Chemistry, University of Munich (LMU), Butenandtstr. 5-13, 81377 Munich Germany.
Inorg Chem. 2020 Oct 19;59(20):15447-15453. doi: 10.1021/acs.inorgchem.0c02431. Epub 2020 Sep 30.
The new Zintl-compounds GeAs ( = Sr, Ba) and BaGeP were synthesized via solid-state reactions, and their structures were determined by single crystal and powder X-ray diffraction. SrGeAs and BaGeAs crystallize in the space group and show complex 3D networks composed of three different Ge-As motifs and As-As bonds with mixed valence of germanium in the oxidation states +2, + 3, and +4. Mixed valences of germanium +3 and +4 occur in BaGeP, which crystallizes in the space group 3̅ with a 3D network built up of GeP dumbbells and P-P bonds. An exceptional 6-fold coordinated germanium resides in the center of a GeP trigonal antiprism. High temperature X-ray diffraction shows thermal stabilities up to 923-953 K. UV-Vis and resistivity measurements reveal a semiconducting nature with small indirect band gaps between 0.02 and 1.6 eV. Electronic band structure calculations confirm the semiconducting state and indicate covalent bonds within the Ge- polyanions.
通过固态反应合成了新型津特耳化合物GeAs(=Sr, Ba)和BaGeP，并通过单晶和粉末X射线衍射确定了它们的结构。SrGeAs和BaGeAs以空间群结晶，并显示出由三种不同的Ge-As基序和具有氧化态为+2、+3和+4的锗混合价的As-As键组成的复杂三维网络。BaGeP中出现锗的+3和+4混合价，它以空间群3̅结晶，具有由GeP哑铃和P-P键构成的三维网络。一个特殊的六配位锗位于一个GeP三角反棱柱的中心。高温X射线衍射表明热稳定性高达923 - 953K。紫外可见光谱和电阻率测量揭示了其半导体性质，间接带隙在0.02到1.6eV之间较小。电子能带结构计算证实了半导体状态，并表明Ge多阴离子内存在共价键。
