Synthesis of Nano-sized Tabular Lindgrenite (Cu3(MoO4)2(OH)2) by Aqueous Precipitation

Lindgrenite (Cu-3(MoO4)(2)(OH)(2)) nanocrystals were synthesized by simple aqueous precipitation at 60 degrees C, using Cu(NO3)(2)center dot 6H(2)O, Na2MoO4 center dot 2H(2)O and NaOH as the starting materials. X-ray Diffraction (XRD) patterns confirm the formation of pure Cu-3(MoO4)(2)(OH)(2) nanocrystals, which belongs to the monoclinic phase with calculated crystal parameters a = 0.53863 nm, b = 1.40006 nm, c = 0.56003 nm, beta = 98.47 degrees, a = gamma = 90 degrees. The energy dispersive X-ray spectrum (EDX) analysis gives an approximate atomic ratio of 3:2: 10 for Cu: Mo: O. The scanning electron microscope(SEM) and transmission electron microscope (TEM) studies show that the as-prepared nanoparticles are well crystallized with tabular structure and the interplanar distances of d(021) and d(121) measured are 0.435 nm and 0.358 nm, coinciding with the theoretical value. It can also be seen that the Cu-3(MoO4)(2)(OH)(2) has a good thermal stability and starts decomposing at 320 degrees C through thermogravimetric-differential thermal analysis (TG-DTA). Moreover, the strong fluorescent property of the Cu-3(MoO4)(2)(OH)(2) is measured, with green emission peak at ca. 530 nm upon excitation at ca. 369 nm. Finally, a possible mechanism for the formation of Cu-3(MoO4)(2)(OH)(2) nanocrystals is proposed.