无水硫酸钙/7778-18-9

白色结晶性粉末。无气味。加热至100℃失去部分结晶水而成为半含水盐(CaS O4?1/2H2O)，称煅石膏。室温时重又成为二水盐，如再加热，则完全脱水成无水盐；即使再加水也不恢复。难溶于水(0.26g/100ml，18℃)，溶液皇中性，有涩味。微溶于甘油。不溶于乙醇。 相对密度2.96。熔点1450℃。
质量标准
  

≥99.99% metals basis：


外观Appearance                                     白色粉末或块状物
纯度Purity                                                 ≥99.99% Based On Trace Metals Analysis
钙Ca                                                           28.5% - 30.3%  (complexometric titration) 
痕量金属分析Trace Metal Analysis        ≤200ppm by ICP Atomic emission

品级Grade                                                             分析纯   
                                                                                  (AR) 
铁Iron(Fe)                                                             ≤0.002%  
含量Assay                                                             ≥97.0%  
氯化物chloride(Cl)                                               ≤0.01%  
干燥失量drying loss                                             ≤1.0%  
盐酸不溶物not dissolved matter in HCL        ≤0.05%  
铵ammonium(NH4)                                            ≤0.03%  
碱金属及镁alkali metal and magnesium         ≤0.5%