Magnesium sulfate is an inorganic salt with the formula MgSO₄ₓ where 0≤x≤7. It is often encountered as the heptahydrate sulfate mineral epsomite, commonly called Epsom salt. The overall global annual usage in the mid-1970s of the monohydrate was 2.3 million tons, of which the majority was used in agriculture.
Formula: MgSO4