FERROUS CHLORIDE FeCL2
Ferrous chloride is used in metallurgy as an electrolytic agent and as a mordant in dyeing. It has been used in the synthesis of penta substituted acyl ferrocenes. In biological research, ferrous chloride is used as a source of Fe2+ ion.
FeCl2.4H2O is 198.83 g/mol and FeCl2 is 126.75 g/mol - This means that 1g of FeCl2.4H2O is equivalent to 0.6375g of FeCl2.
Iron(II)chloride tetrahydrateisusedas a reducing agent in metallurgy, in pharmaceutical preparations, as a mordant in dyeing and in sewage treatment. ... It is the precursor to hydratediron(III) oxides that are magnetic pigments.
Dosage
FeCl2.4H2O is 198.83 g/mol and FeCl2 is 126.75 g/mol - this means that 1g of FeCl2 . 4H2O is equivalent to 0.6375g of FeCl2. You could also probably make the tetrahydrate by dissolving the anhydrous chloride in water and then letting it evaporate (without heat) to leave the hydrated product.