Growth, single-crystal structure, and magnetic properties of the double molybdate KYb(MoO4)2

Crystals of the rare earth double molybdate KYb(MoO4)(2) were grown by spontaneous nucleation from a K2Mo4O13 flux. The typical crystals were colorless and elongated, well-developed plates. The material has been characterized by powder X-ray diffraction (PXRD), energy-dispersive X-ray spectrometry (EDS), and Raman spectroscopy methods. The structural properties have been investigated through single-crystal X-ray diffraction at room temperature. KYb(MoO4)(2) crystallizes in the orthorhombic symmetry, space group Pbcn (No. 60), a = 5.0395(2), b = 18.2821(9), c = 7.8635(4) angstrom, and Z = 4. A complete ordering of the Yb3+ and Mo6+ cations has been found. The Yb3+ ions are located in distorted YbO8 antiprisms which form chains of edge-sharing, aligned along the c-axis while the Mo6+ ions are placed in a slightly deformed tetrahedral environment of oxygen atoms. Double bridge modes of the "Mo2O8 dimers'' have been identified in the unpolarized Raman spectra. The temperature-dependent magnetic susceptibility of KYb(MoO4)(2) follows a Curie-Weiss law with a Weiss constant of -52 K.