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Magnesium hydroxide



Name Magnesium hydroxide
Chemical formula Mg(OH)2
Appearance White solid


Formula weight 58.3 amu
Melting point Decomposes at 623 K (350 °C)
Density 2.4 ×103 kg/m3
Crystal structure ?
Solubility 0.0012 g in 100g water


ΔfH0gas -561 kJ/mol
ΔfH0solid -925 kJ/mol
S0solid 63 J/mol·K


Ingestion Safe in small amounts, but large amounts can be dangerous.
Inhalation May cause irritation.
Skin May cause irritation.
Eyes May cause irritation.
More info Hazardous Chemical Database
SI units were used where possible. Unless otherwise stated, standard conditions were used.

Disclaimer and references

Magnesium hydroxide, Mg(OH)2, otherwise known as milk of magnesia, is commonly used as an antacid or a laxative. The mineral form of magnesium hydroxide is known as brucite. Magnesium hydroxide interferes with the absorption of folic acid and iron. The diarrhea caused by magnesium hydroxide carries away much of the body's supply of potassium, and failure to take extra potassium will lead to muscle cramps.