【摘要】 本文由粉状白钨酸制备了偏钨酸铵,该化合物容易自澄清溶液中以削角正八面体形状结晶,晶体分子式为（NH₄）₆[H₂(W₃O₁₀)₄]·20H₂O。由多晶X光衍射方法确定它属立方晶系,经粉末衍射图谱的指标化求得晶胞参数α=18.08,晶胞内含4个分子。更多还原

【Abstract】 After we succeeded in preparing white powdery tungstic acid hitherto not described in literature, we have found that on account of its reactivity, different from tungstic acid in yellow form, white powdery tungstic acid can be well used for preparing a variety of compounds including different kinds of salts of meta-tungstic acid as well as certain heteropoly tungstic acid and their salts.Ammonium metatungstate, AMT, prepared by neutralizing white powdery tungstic acid with ammonium bicarbonate gives a perfectly clear, rather concentrated solution, then well defined crystals at room temperature. Although the crystals thus prepared rather readily lose part of water of hydration, as revealed in thermal analysis, we have succeeded in measuring its X-ray diffraction pattern not yet revealed in literature. The diffraction pattern of AMT crystal has been found as a =18.08 A, Z = 4. The molecular formula of AMT can be expressed as (NH4)6[H2(W3O10)4]·20H2O.更多还原