Crystal structure, Raman characterization, and magnetic properties of the hydrate RbYb(MoO4)2, H2O

The millimeter-sized single crystals of RbYb(MoO4)(2), H2O monohydrate were successfully grown using the high-temperature self-flux method. This colorless and shiny double molybdate crystallizes in the monoclinic system with space group C2/c. Its lamellar structure can be described with YbO8 regular square antiprisms sharing edges into chains aligned along the [001] direction. A layered arrangement occurs perpendicularly to the [010] direction with MoO4 tetrahedra and YbO8 polyhedra associated in complex anionic layers alternating with cationic layers made of Rb+ ions surrounded by eight oxygen atoms into flattened RbO8 square antiprisms. Raman investigation at room temperature shows a weak vibration at 737 cm(-1) attributed to the existence of pseudo-double-bridges Mo-{O-2}-Mo, while the absence of bands in the 500-700 cm(-1) frequency range confirms the lack of covalent Mo-O-Mo single-bridge. Magnetic characterizations suggest that the title compound presents an antiferromagnetic coupling between the Yb3+ centers at T <= 10 K.