Physical State and Sensory Characteristics
Magnesium sulfate is a colorless, odorless, slightly bitter white solid, commonly found as a heptahydrate (Epsom salt).
It is highly soluble in water (approximately 700 grams dissolve in 1 liter of water at room temperature) and also readily soluble in organic solvents such as glycerol and alcohol.
Anhydrous magnesium sulfate is hygroscopic and is commonly used as a desiccant in organic synthesis.
Chemical Properties
Hydrate Forms: In addition to the heptahydrate, other types of hydrates exist.
pH Value: Magnesium sulfate solution is neutral (pH≈6.0), not acidic.
Thermal Stability: When heated to 250℃, the heptahydrate loses its water of crystallization to form anhydrous salt; further heating decomposes it into magnesium oxide.
Hydrolysis Reaction: Upon dissolution in water, it decomposes into magnesium ions (Mg²⁺) and sulfate ions (SO₄²⁻).
Other Properties
Magnesium ions have an absorption effect on high-frequency sound in seawater.
