Quaternary Germanide Arsenides ZrCuGeAs and HfCuGeAs

The quaternary germanide arsenides ZrCuGeAs and HfCuGeAs were prepared by reaction of “ZrCuGe” or “HfCuGe” precursor materials with As at 800 °C. They are new representatives of the ZrCuSiAs-type structure (tetragonal, space group P4/nmm, Z = 2, Pearson symbol tP8), as determined by single-crystal X-ray diffraction on ZrCuGeAs (a = 3.7155(2) A, c = 9.5644(6) A) and powder X-ray diffraction on HfCuGeAs (a = 3.6935(3) A, c = 9.5557(9) A). They belong in the small category of ZrCuSiAs-type compounds exhibiting strong covalent bonding in three dimensions, as reflected in their location in a structure map and as confirmed by band structure calculations. X-ray photoelectron spectroscopy provides evidence for anionic As atoms. Both compounds exhibit temperature-independent Pauli paramagnetism.