Direct hydrothermal synthesis of metal intercalated hexagonal molybdates ,Mx Mo6–x/3O18–x(OH)x.yH2O (M = Li, Rb, Cs, NH4)

Here we report direct hydrothermal synthesis of a few hexagonal molybdates with composition MX^+MO^sigma+( sigma –X/3 O18-X)(OH)x.yH2O (M = Li, Rb, Cs, NH4). The molybdates crystallize in the space group P63/m with a ~ 10,50and c ~ 3,7Å . Unlike previous studies, our work suggests that hexagonal molybdates could be stabilized in the presence of monovalent cations with varying ionic size (smaller lithium to larger cesium) under hydrothermal condition. The phases showed exceptional thermal stability till 550C.