Hexagonal Double Perovskite Cs2AgCrCl6. Issue 3 (31st October 2018) - Zhou, Yuqiao
Abstract : The quaternary halide Cs2 AgCrCl6 was prepared in the form of dark purple crystals by reaction of CsCl, AgCl, and CrCl3, at 700 °C. It crystallizes in the trigonal Ba2 NiTeO6 ‐type structure [space group R 3 m, Z = 6, a = 7.2692(4) Å, c = 36.443(2) Å] belonging to the family of perovskite polytypes containing sequences of hexagonal close‐packed layers. Groups of three face‐sharing octahedra, which are occupied in the sequence Ag–Cr–Ag, are connected through corner‐sharing by Cr‐centered octahedra. The UV/Vis/NIR diffuse reflectance spectrum shows absorptions arising from d–d transitions typical of octahedral Cr 3+ complexes, as confirmed by electronic structure calculations. The compound melts at 506 °C. Magnetic measurements revealed simple paramagnetic behavior consistent with the presence of isolated Cr 3+ ions. Abstract :