Magnesium
Lightweight metal essential to life and industry.
Magnesium is a chemical element with symbol Mg and atomic number 12. It is a shiny gray metal, the eighth most abundant element in Earth's crust and the fourth most common element in the Earth, making up 13% of the planet's mass.
- symbol
- Mg
- atomic_number
- 12
- group
- alkaline earth metals (group 2)
- abundance_in_earth_crust
- 8th most abundant
- abundance_in_human_body
- 11th most abundant by mass
- primary_use
- component in strong and lightweight alloys
Lore & Background
Magnesium is produced in large, aging stars by the sequential addition of three helium nuclei to a carbon nucleus. When such stars explode as supernovas, much of the magnesium is expelled into the interstellar medium, where it may recycle into new star systems. It is the third most abundant element dissolved in seawater, after sodium and chlorine. Elemental magnesium is a gray-white lightweight metal, two-thirds the density of aluminium. It has the lowest melting and boiling points of all the alkaline earth metals. Pure polycrystalline magnesium is brittle, but becomes much more malleable when alloyed with small amounts of other metals, such as 1% aluminium. The metal is obtained mainly by electrolysis of magnesium salts obtained from brine. Magnesium reacts readily with air to form a thin passivation coating of magnesium oxide. It burns with a brilliant-white light. It reacts with water at room temperature, though more slowly than calcium, and reacts exothermically with most acids. Organomagnesium compounds, such as Grignard reagents, are widespread in organic chemistry.
Reader's Guide
Magnesium's significance spans multiple domains. In industry, it is used primarily as a component in strong and lightweight alloys that contain aluminium, though consumption of magnesium alloys has been historically limited by tendencies to corrode, creep at high temperatures, and combust. Its use as a reducing agent and in thermite ignition highlights its chemical reactivity. Medicinally, magnesium compounds are used as laxatives and antacids, and to stabilize abnormal nerve excitation or blood vessel spasm in conditions such as eclampsia. In cosmology, magnesium is produced in aging stars and expelled by supernovas, recycling into new star systems. The isotope 26Mg has application in isotopic geology as a radiogenic daughter product of 26Al, helping to date early Solar System objects. Magnesium hydride has been investigated as a way to store hydrogen.
Did You Know?
- Magnesium is the eighth most abundant element in Earth's crust and the fourth most common element in the Earth, making up 13% of the planet's mass.
- The free metal burns with a brilliant-white light.
- The isotope 26Mg is a radiogenic daughter product of 26Al, used in isotopic geology.
Frequently Asked Questions
Who is Magnesium?
Magnesium is a shiny gray alkaline earth metal carrying the symbol Mg and atomic number 12, placed in Group 2 of the periodic table. It ranks as the eighth most abundant element in Earth's crust and makes up roughly 13% of the planet's total mass.
How does Magnesium's story end?
Because it is a highly reactive metal, Magnesium readily sheds its two outer electrons to lock into ionic compounds such as magnesium oxide, effectively giving itself away in a stable bond. In the human body, once its enzymatic duties are complete, the kidneys filter the excess out through urine.
Why is Magnesium so important?
It is the eleventh most abundant element in the human body by mass and underpins hundreds of metabolic reactions, so no cell can truly function without it. On the materials side, its low density paired with high strength makes it a go-to ingredient for lightweight structural alloys.
Who are Magnesium's allies in the periodic table?
Magnesium belongs to the alkaline earth metals of Group 2, sharing its two-valence-electron chemistry with beryllium, calcium, strontium, barium, and radium. This family is well known for producing bright-reactive metals that all form +2 cations.
More in Chemistry & Materials 1-24
Elsewhere in the Chemistry & Materials universe
Spotted an error? Know more?
This is a living reference — every entry is fact-audited, and reader corrections feed straight into our audit queue. Suggest an edit · See this site's audit record