The Reduced Nitridogermanates(III) Ca₆ [Ge₂ N₆ ] and Sr₆ [Ge₂ N₆ ] with Ge-Ge Bonds

The first nitridogermanates(III) Ca₆ [Ge₂ N₆ ] and Sr₆ [Ge₂ N₆ ] were synthesized from sodium flux and structurally characterized by powder and single crystal X-ray diffraction, respectively. They crystallize isostructurally to each other and homeotypic to Ca₆ [Cr₂ N₆ ]H in space group R $$ . They feature unprecedented, mutually isolated, ethane-like [Ge^III ₂ N₆ ]^12- anions in a staggered conformation. The compounds are semiconductors according to resistivity measurements and electronic structure calculations, yielding band gaps of 1.1 eV for Ca₆ [Ge₂ N₆ ] and 0.2 eV for Sr₆ [Ge₂ N₆ ].