Synonyms: Nickel(II) sulfate hexahydrate CAS: 10101-97-0 Molecular Formula: NiSO4 · 6H2O Molecular Weight: 262.85 g/mol Test Specification Appearance (Color) Green Appearance (Form) Crystals Nickel (Ni) 22.0 - 23.0% Cadmium (Cd) 5 ppm max. Calcium (Ca) 10 ppm max. Cobalt (Co) 200 ppm max. Copper (Cu) 5 ppm max. Iron (Fe) 10 ppm max. Lead (Pb) 5 ppm max. Zinc (Zn) 5 ppm max. Insoluble in Water 50 ppm max.