二水合钨酸钠

性状：无色结晶或白色结晶性粉末。在干燥空气中风化。密封于阴凉处保存。

技术条件

含量（Na2WO4·2H2O）,%                                     ≥99.5

                               杂质最高含量（以%计）

澄清度试验，号                                                         3

碱度（以OH计），mmol/g                                       0.04

水不溶物                                                                    0.01

氯化物（Cl）                                                              0.005

硫酸盐（SO4）                                                           0.01

总氮量（N）                                                              0.001

铁（Fe）                                                                    0.0005

砷（As）                                                                    0.0005

重金属（以Pb计）                                                      0.0005