Magnesium

Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a light, silvery-white alkaline earth metal and the eighth most abundant element in Earth's crust. It occurs in minerals such as magnesite, dolomite, and brucite and is present in seawater as Mg2+ ions.

Magnesium metal is highly reactive, forming a protective oxide layer in air. It burns with a bright white flame when ignited and has a high strength-to-weight ratio, making it valuable for lightweight alloys in aerospace, automotive, and electronics. Pure magnesium reacts with water under certain conditions.

Production and uses: It is produced mainly by electrolysis of molten magnesium chloride obtained from seawater or brine. The principal applications are in magnesium alloys (notably with aluminum and zinc), refractories, and chemical specialties. Magnesium compounds such as oxide, hydroxide, and chloride have additional industrial and biomedical uses.

Biological role: Magnesium is an essential mineral involved in hundreds of enzyme reactions, energy metabolism, and synthesis of DNA, RNA, and proteins. It supports normal muscle and nerve function, heart rhythm, and bone health. Dietary sources include leafy greens, nuts, seeds, whole grains, and legumes, with intake varying by age and sex.

Deficiency and safety: Inadequate intake can cause cramps, weakness, and arrhythmias. Excess magnesium from supplements can cause diarrhea and abdominal cramps, and high levels pose risks for people with kidney impairment. Magnesium is also used medically as a laxative or antacid when appropriate.