Al_(13) Based Molybdate Crystals with Multimorphologies Synthesized from P-Mo(V) Heteropoly Compounds

The Al13 based molybdate crystals with multimorphologies were synthesized via a direct mixing and aging method. The heteropoly compounds of H3PMo12O40·nH2O, H4PMo11VO40·nH2O and (NH4)6P2Mo18O62·nH2O (abbr. P-Mo(v) heteropoly compounds) were employed as the molybdate sources. The corresponding morphology and size of the molybdate crystals is trimetrical-prismy like (80 μm × 30 μm), star-like (30 μm × 10 μm) and leaf-like (500 μm × 150 μm). XRD patterns show that the Al13 based molybdates with multimorphologies are of high crystallinity, and have strong and sharp peaks (2θ) at 6.65°, 8.00° and 14.16°. However, when Na2MoO4·2H2O was used, there were only amorphous clusters in a similar process. According to the results of ICP, FTIR and TG / DTG, the chemical formula of the Al13 based molybdate crystals is Na[AlO4Al12(OH)24(H2O)12][MoO4]4·8H2O. The probable crystal growth mechanism is proposed.