... 2)package,25kg/bag 3)Usage, additives,fertilizer,water scavenging agent iron sulfate heptahydrateMolecular Formula: FeSO4·(X) H20 (X=1 ... green crystal, relative density: 1.895 ~1.898 . m.p.: 64oC. Easy weathering in dry air .Into tetrahydrate (56.6 ... oxide red and indigo-blue; as mordant ,tanning agent,water scavenging agent,wood preservative,disinfectant and heliograph etc.as fertilizer, herbicide ...