... 2)package,25kg/bag 3)Usage, additives,fertilizer,water scavenging agent iron sulfate heptahydrateMolecular Formula: FeSO4·(X) H20 (X=1 or ... : 1.895 ~1.898 . m.p.: 64oC. Easy weathering in dry air .Into tetrahydrate (56.6°C),monohydrate (65°C).In ... , iron oxide red and indigo-blue; as mordant ,tanning agent,water scavenging agent,wood preservative,disinfectant and heliograph etc.as fertilizer, herbicide ...