报道了一种新奇的磷钒酸盐［ＮＨ４］４Ｈ［ＰＭｏ８ＶⅣ４ＶⅤ２Ｏ４２］·２４Ｈ２Ｏ的合成方法，用元素分析、ＥＰＲ、ＩＲ、ＵＶ谱和ＴＧ等手段进行了表征，并用Ｘ射线衍射法测定了晶体结构．结果表明，该杂多酸盐属于四方晶系，空间群Ｐ４／ｍｎｃ，ａ＝ｂ＝１２５９２（２）ｎｍ，ｃ＝１７５６５（４）ｎｍ，Ｖ＝２７８４８（８）ｎｍ３，Ｚ＝２．杂多阴离子具有双帽ｐｓｅｕｄｏＫｅｇｇｉｎ结构，不仅其中的８个金属位置被Ｖ和Ｍｏ无序占有，而且整个磷钼钒酸盐杂多阴离子的取向也是无序的．还应用ＥＨＭＯ方法研究了簇阴离子的电子结构 A novel method for the synthesis of [NH4] 4H [PMMA8VIV4VV2O42] · 24H2O was reported and characterized by means of elemental analysis, EPR, IR, UV spectrum and TG. The crystal structure was determined by X-ray diffraction . The results show that the heteropolyacid salt belongs to the tetragonal crystal system. The space group P4 / mnc, a = b = 12592 (2) nm, c = 17565 (4) nm and V = 27848 (8) nm3 , Z = 2. Heteropolyanions have a double-cap pseudo-Keggin structure, in which not only eight metal sites are occupied by V and Mo disorderly, but also the entire phosphomolybdovanadate heteropolyanions are also disordered. The electronic structure of cluster anions was also studied by EHMO method