Items Standard Appearance White crystalline powder Melting Point(ºC) 160.0 to 162.0ºC Chloride(C1) Not more than0.02% Ammonium(NH4) Not more than0.02% Sulfate(SO4) Not more than 0.02% Heavy metals(Pb) Not more than 10ppm Iron(Fe) Not more than 10ppm Arsenic(As2O3) Not more than 1ppm Loss on drying Not more than 0.50% Residue on ignition Not more than0.1% Assay 99.0-101.0%