**2.1 Syntheses of arsenomolybdates**

Arsenomolybdates crystals reported were almost synthesized via self-assembly processes using hydrothermal method (**Figure 2**). Many factors in the synthetic process should be considered, such as reaction time and temperature, concentration of staring materials, compactness, pH values, and so on. The some experiments indicate that the temperatures are in the range of 110–180°C for srsenomolybdates synthesized, when the pH value of the mixture is adjusted to approximately 3–6.8, [HxAs2Mo6O26] (6 x) (abbreviated {As2Mo6}), [(MO6)(As3O3)2Mo6O18] 4 (abbreviated {As6Mo6}) and [AsIIIAsVMo9O34] <sup>6</sup> (abbreviated {As2Mo9}) types were easy to formed, when the pH value is within the range of 2.5–5.5 and 2–4, [AsMo12O40] <sup>3</sup> (abbreviated {AsMo12}) and [As2Mo18O62] <sup>6</sup> (abbreviated {As2Mo18}) types were successfully synthesized. At the same time, the choice of transition metal, organic ligand, and molybdenic source have also affect for

*Arsenomolybdates for Photocatalytic Degradation of Organic Dyes DOI: http://dx.doi.org/10.5772/intechopen.92878*

**Figure 2.** *The synthesis chart of arsenomolybdates crystal.*

arsenomolybdates crystals. Therefore, further exploration of synthetic conditions is necessary, which can provide more experimental data for arsenomolybdates.
