外观Appearance                                  黄色至黄橙色粉末
X-射线衍射分析X-Ray Diffraction         Conforms to standard
ICP                                                      Confirms
纯度Purity                                           >99.0% (T)
不溶于NaOH物质insoluble matter in NaOH  ≤0.2%
干燥损失loss on ignition                             ≤8%

项目                                                  分析纯  
                                                            (AR)
钙calcium                                            ≤0.01% 
磷phosphorus                                     ≤0.01% 
硫化合物sulfur compounds                 ≤0.02% 
钼molybdenum                                   ≤0.02% 
砷arsenic                                             ≤0.02% 
铁iron                                                 ≤0.005% 
灼烧残渣residue on ignition                 ≤0.15% 
灼烧失重calcination loss                     7.0~15.0%

99.999% metals basis:

外观Appearance                                   Yellow Powder
X-射线衍射分析X-Ray Diffraction          Conforms to standard
纯度Purity                                            ≥99.999% Based on Trace Metals Impurities of ICP
ICP Assay                                             Confirms Tungstic component
痕量金属分析total metallic impurities    ≤20ppm by ICP Atomic emission