Syntheses, Crystal Structures and Characterization of Two Zeotype Crystals of K4[Cr30（H2O） 3（OOCH） 6] 2[ P2W18O62]· 9.5H2 O and K4[ Cr3O（ H2O）3（ OOCH）6 ]2[ H3 P2 W17Co（H2O） O61]· 20H2O

Two novel zeotype crystals, K4[Cr30（H2O） 3（OOCH） 6] 2[ P2W18O62]· 9.5H2 O and K4[ Cr3O（ H2O）3（ OOCH）6 ]2[ H3 P2 W17Co（H2O） O61]· 20H2O（2） , were synthesized and their structures were determined using X-ray single crystal diffraction. Crystal data： C12H43O103.5K4Cr6P2W18（1）, hexagonal P6（3）/m, α= 1. 5895（2） nm, b=1.5895（2） nm, c =2.1620（4） nm, α=90°, β=90°, γ= 120°, V=4.7305（13） nm^3, Z=2, R1 =0,0726, ωR2 =0. 1542; C6H57O98K4Cr3CoP2W17 （2）, hexagonal P6（3）/mmc, α = 1.61328（3） nm, b = 1.61328（3） nm, c=2.06613（9） nm, α=90°, β=90°, γ=120°, V=4.6570（2） nm^3, Z=2, R1 =0.0377, ωR2 =0. 1070. These crystals were characterized using elemental analysis, IR, TG-DTA, and XRD. It was found that the polyoxometalate anions maintained Wells-Dawson structure for crystal I and laeunary Wens-Dawson structure for crystal 2. Thermal analysis showed that crystal 1 lost the water of crystallization at 132 ℃, whereas crystal 2 lost the water of crystallization at 100 ℃. Crystal 1 could reversibly desorb and adsorb water molecules and its crystal structure could be restored after re-adsorbing the water molecules. It was also found from the XRD patterns that the void size of crystal 2 is smaller compared with that of crystal 1, which is attributed to the higher anion charges.