a Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
b Institute of Nanostructured Functional Materials, Huanghe Science and Technology College, Zhengzhou, Henan 450006, China
Received 11 February 2012. Revised 13 March 2012. Accepted 14 March 2012. Available online 22 March 2012.
A series of layered compounds ACrV2O7 (A=Na, K, Rb, Cs) were investigated by means of powder X-ray diffraction technique, thermal analysis and IR spectroscopy. As a new member in this family, the structure of CsCrV2O7 is confirmed by Rietveld refinement applying powder X-ray diffraction data. Isostructural NaCrV2O7 was obtained by ion-exchange reaction of KCrV2O7 in NaNO3 melt under 350 °C and was testified to be a metastable phase. These compounds crystallize in a monoclinic structure in the space group P2/c, and consist of planar CrV2O7− slabs interleaved by alkali-metal cations. ACrV2O7 (A=K, Rb, Cs) present decreasing melting points and characteristic vibration of V=O bond in IR spectra. Magnetic measurements reveal weak antiferromagnetic interactions between Cr3+ cations in the isolated chains.
A series of layered chromium vanadates ACrV2O7 (A=Na, K, Rb, Cs) have been synthesized by direct solid state reactions and ion-exchange routes. The interlayer alkali-metal cations were testified ion-exchangeable by some smaller monovalent cations.