熔点  230 °C (dec.)(lit.)
密度  0.981 g/mL at 25 °C 

品级Grade                                ACS级   
                                     (ACS reagent, 90 %) 
外观Appearance                          暗绿色至棕色、黑色粉末或结晶
红外光谱鉴别Infrared spectrometry       Conforms
纯度Purity                              ≥90.0% (HPLC) 
λ                                       614 - 618 nm 
                                        c = 0.01g/L, Water 
消光系数Extinction Coefficient          ≥25000 
λ                                       394 - 406 nm
消光系数Extinction Coefficient          ≥8000  
λ                                       306 - 310 nm 
消光系数Extinction Coefficient          ≥10000 
pH变色域Transition interval:            pH 3.8 (yellow) to pH 5.2 (blue)
Visual Interval                         Pass 
                                        pH 3.8 = Yellow  
Visual Interval                         Pass 
                                        pH 4.5 = Green 
Visual Interval                         Pass 
                                        pH 5.4 = Blue 
不溶物Insoluble Matter.                c = 0.1g/100ml; Water


品级Grade                                分析纯   
                                          (AR) 
外观Appearance                          Dark green to black powder or crystals
红外光谱鉴别Infrared spectrum           Conforms to structure
纯度Purity(HPLC)                        ≥90.0%  
PH变色范围Visual range                  3.8(yellow)-5.4(blue) 
灼烧残渣Residue on ignition(as sulfate) 8.5-11.5% 

项目（name）                     指示剂（Ind）
                              (indicator grade） 
水溶解试验                        合格 
PH变色范围                       3.8(黄色)-5.4(蓝色) 
灼烧残渣(以硫酸盐计)             8.5-11.5% 

PH指示剂(pH 3.8-5.4)。