magnesium

American  

[mag-nee-zee-uhm, -zhuhm, -shee-uhm] / mægˈni zi əm, -ʒəm, -ʃi əm /

noun

Chemistry.

• magnesiums
  plural

1. a light, ductile, silver-white, metallic element that burns with a dazzling white light, used in lightweight alloys, flares, fireworks, in the manufacture of flashbulbs, optical mirrors, and precision instruments, and as a zinc substitute in batteries. Mg; 24.312; 12; 1.74 at 20°C.

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magnesium British  

/ mæɡˈniːzɪəm /

noun

1. a light silvery-white metallic element of the alkaline earth series that burns with an intense white flame, occurring principally in magnesite, dolomite, and carnallite: used in light structural alloys, flashbulbs, flares, and fireworks. Symbol: Mg; atomic no: 12; atomic wt: 24.3050; valency: 2; relative density: 1.738; melting pt: 650°C; boiling pt: 1090°C

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magnesium Scientific  

/ măg-nē′zē-əm /

1. A lightweight, moderately hard, silvery-white metallic element of the alkaline-earth group that burns with an intense white flame. It is an essential component of chlorophyll and is used in lightweight alloys, flash photography, and fireworks. Atomic number 12; atomic weight 24.305; melting point 649°C; boiling point 1,090°C; specific gravity 1.74 (at 20°C); valence 2.

2. See Periodic Table

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Other Word Forms

Noun Inflected Forms

• magnesiums
  plural

Etymology

Origin of magnesium

From New Latin, dating back to 1800–10; see origin at magnesia, -ium

Compare meaning

How does magnesium compare to similar and commonly confused words? Explore the most common comparisons:

• magnesium vs. magnesium oxide

Explanation

Magnesium is a shiny metallic chemical element, and it's also a mineral that humans and other organisms need to be healthy. In nature, magnesium is only found combined with other elements, never on its own. When scientists isolate magnesium from these compounds, it looks silvery-white. Magnesium is an excellent conductor of electricity, and it burns brightly. It's used to make fireworks and flares, and it's often combined with aluminum and zinc to make lightweight metal alloys. Ionized magnesium is necessary for our bodies to function properly: It is involved in over 300 biochemical reactions in the human body. Many people take supplements containing magnesium compounds.

Example Sentences

See Examples For:

magnesium magnesiums

Their results suggest that the 2′-OH allows RNA to interact more strongly with magnesium ions.

From Science Daily ● Oct. 2, 2026

Mafic magma has relatively low viscosity and is rich in magnesium and iron.

From Science Daily ● Sep. 14, 2026

Sleep scores, magnesium, white noise machines - what was once the simple act of sleeping has become a minefield.

From BBC ● Sep. 3, 2026

If the current trend continues, the magnesium that American industry depends on could disappear from world markets by 2030 without Beijing imposing a single sanction.

From The Wall Street Journal ● Aug. 24, 2026

All we need do is procure a sample of, say, Phobos or a comet and examine its magnesium isotopes.

From "Cosmos" by Carl Sagan

Not only are the "bound" magnesiums more bioavailable, but in being so they do not tend to be dumped into the intestines quickly for that well known laxative effect.

From New York Times ● Jan. 5, 2018