Magnesium (Mg)

Magnesium is a chemical element with the atomic number 12 in the periodic table. Born in the Universe from supernovas of aged stars, the occurrence of this element amounts to 2.5% of Earth’s crust, mainly as a part of the magnesium oxide compound. Magnesium is also found in Earth’s mantle. 

As a member of the alkaline earth metals family of the periodic table, this vitally important element for all life on Earth has two valence electrons. Being included in the electrolyte balance of cells, magnesium is one of the essential elements that have an extremely important role in the health of our body and brain. 

Chemical and Physical Properties of Magnesium

Atomic number12
Atomic weight (mass)24.305 g.mol-1
ColorSilvery-gray metal
Physical stateSolid at room temperature
Half-lifeFrom less than 5(3) picoseconds to 20.915 hours
Melting point650°C, 1202°F, 923 K
Boiling point1090°C, 1994°F, 1363 K
Ionic radius0.065 nm
Most characteristic isotope24Mg, 25Mg, 26Mg
Electronic shell[Ne] 3s2
The energy of the first ionization737.5 kJ.mol-1
The energy of the second ionization1450 kJ.mol-1
Discovery dateIn 1755 by Joseph Black

Magnesium is the second lightest member of the alkaline earth metals family of the periodic table. Classified under the symbol Mg, atomic number 12, atomic mass of 24.305 g.mol-1, and electron configuration [Ne] 3s2, magnesium is a very soft, ductile, and lightweight metal.

It reaches its boiling point at 1090°C, 1994°F, 1363 K, while the melting point is achieved at 650°C, 1202°F, 923 K. In addition, this chemical element has an electronegativity of 1.2 according to Pauling, whereas the atomic radius according to van der Waals is 0.16 nm. 

This s-block element has a hexagonal close-packed crystal structure and two electrons in the outermost electron shell. Being a highly reactive element, magnesium can be passivated by a thin layer of oxide that forms on the surface of the magnesium metal when it’s exposed to air. The resulting tarnish gives a dull appearance to the metal instead of the characteristic silvery luster but adds to the strong anti-corrosive properties of this element. 

Magnesium burns with a brilliant white light. The flames of magnesium cannot be extinguished with water. On the contrary, adding H2O to burning magnesium creates a more volatile reaction with a bigger flare-up. 

How Was Magnesium Discovered?

Magnesium and some of its beneficial properties regarding health were known to people since ancient times. The first evidence of magnesium’s practical application leads to the prefecture of Magnesia, Greece, where the alchemists of the time were widely using a form of magnesium carbonate (Mg(CO)3) known as magnesia alba (or: white magnesia) for medicinal purposes. 

Since magnesium frequently occurs in mineral ores that contain calcium, for a long time it was thought that calcium and magnesium are the same substance. This triggered the curiosity of the Scottish chemist Joseph Black (1728 – 1799). Thus, in 1755, this professor of Anatomy and Chemistry at the University of Glasgow attempted an experiment to confirm his belief that the magnesia alba (magnesium carbonate) is a compound of “a strange new earth element and a fixed air”. 

In his revolutionary chemical trial, Black tried to heat magnesite and limestone ores, which helped him distinguish magnesia (magnesium oxide, MgO) from lime (calcium oxide, CaO). Based upon the resulting scientific evidence, this Glasgow chemist proposed the existence of the new chemical element magnesium.

The Contribution of Sir Humphry Davy (1778 – 1829)

In 1792, the Hungarian chemist Antal Ruprecht (1748-1818) succeeded in producing the first impure form of the magnesium metal by heating magnesia (magnesium oxide, MgO) with charcoal. Ruprecht believed that the alkaline earth metals were compounds, not elements. 

This claim of the Hungarian chemist was confirmed by Sir Humphrey Davy in 1808 when he isolated the first pure elemental form of magnesium by the method of electrolysis. To achieve this, Sir Davy mixed a paste made of moist magnesium oxide and red mercury oxide. He also used a piece of mercury metal as a negative electrode and platinum as a positive electrode. The electricity that was conducted through the paste formed a magnesium-mercury amalgam. Then, Sir Davy heated the amalgam to remove the mercury which resulted in the pure elemental form of magnesium.

How Did Magnesium Get Its Name?

Sir Humphry Davy’s first choice of a name for element 12 was ‘magnium’, but eventually he changed his mind and the name of the new element was changed to the currently known ‘magnesium’, after Greek region Magnesia. Namely, this district in Greece was considered to be the location where magnesium was first obtained by the ancient civilizations.

Where Can You Find Magnesium?

Despite being the seventh most abundant chemical element on our Planet, magnesium does not occur naturally in its free form. As a result of magnesium’s high reactivity, this mineral typically occurs as part of the mineral compounds, such as mineral rock formations (dolomite, magnetite, olivine, and serpentine), the underground brines, the seawaters, as well as in the salty layers.

For commercial purposes, nowadays magnesium is mostly obtained from the mineral compounds magnesite (MgCO3), brucite (Mg (OH)2), magnesium chloride enriched brine, and seawater. The largest magnesium ore deposits in the world are located in China, Austria, Brazil, Canada, Greece, Turkey, and the United States.

Magnesium in Everyday Life

Magnesium is a vitally important natural element for all life forms. By participating in the metabolic processes, this mineral contributes to the production of energy in all live systems of our Planet. It also has several other highly beneficial applications:

  • Magnesium hydroxide (Mg(OH)2) is a result of the reaction between magnesia and water molecules. Also labeled as “milk of magnesia”, this magnesium compound is frequently used in medicine as a laxative for the treatment of chronic constipation, or as an antacid agent in case of heartburn, an upset stomach, or indigestion.
  • Hydrated magnesium sulphate (MgSO4·7H2O), popularly known as Epsom salt, is used in medicine for soothing muscle aches, loosen stiff joints, decrease swelling and inflammation, and promote overall recovery of the musculoskeletal system of the body. In gardening, this mineral compound is often used as a chemical agent that supports the growth of the plants, increases chlorophyll production, produces bigger and more plentiful blooms in flowering plants, and deters pests from the gardens. 
  • Magnesium fluoride has a practical application in the manufacturing of optical lenses, contributing to the reduction of both reflection and glare.
  • Caustic-calcined magnesia has a vast number of industrial, agricultural, and environmental applications. It’s also used in the construction for the production of magnesium oxychloride and oxysulfate cement, further applied in the flooring industry.
  • This chemical element is often alloyed with other metals, such as aluminum, the manufacture of lightweight but strong metal items, such as drink cans, car parts, etc. 
  • Due to its flammable properties, magnesium is one of the main substances used in the manufacturing of fireworks.

Magnesium and Health

If there is one word to describe magnesium and its importance to our body, it would be energy. Namely, the main role of magnesium is to support the metabolic processes that generate energy – not only in the human body but in plants and animals, too. For this reason, both very low and very high magnesium levels may result in adverse health effects. 

Apart from energy production, this vital nutrient plays a significant role in the health of the nerves, muscles, and bones. Magnesium is involved in the metabolism of carbohydrates which supports blood glucose control. 

Furthermore, magnesium has an impact on the hormones that control the regulation of calcium and vitamin D that affects the health of the bones and the skeletal system of the body. In this way, adequate magnesium intake is directly connected with a lower risk of osteoporosis in older adults. This key mineral also takes a highly significant part in the control and regulation of blood pressure. 

Magnesium plays an important role in more than 300 metabolic processes in our body. For this reason, when there’s not enough magnesium in the diet, it can lead to many serious health problems.

What Is Magnesium Deficiency?

Hypomagnesemia, or magnesium deficiency, occurs when the recommended intake of magnesium has not been met. When the levels of magnesium in the body are insufficient, all metabolic processes suffer which results in many severe health disorders. 

Magnesium deficiency is a risk factor for osteoporosis by lowering the blood levels of calcium as the chief building block of the bones. Furthermore, it triggers cardiovascular diseases by influencing high blood pressure values, leads to the development of mental problems, and heightened risk of type 2 diabetes by interrupting the normal metabolism of carbohydrates in the body.

Several clinical trials performed at the Oregon State University, United States, point out the direct connection between magnesium deficiency and asthmatic attacks in both children and adults. According to the scientific evidence derived from these trials, magnesium administered as an intravenous therapy in patients with asthma exacerbations has a direct impact on the improvement of lung function.

What Are the Symptoms of Magnesium Deficiency?

Typically, the symptoms of magnesium deficiency do not occur until the levels of this essential mineral our body needs are severely low. In case of drastically low magnesium levels, the affected individual may experience:

  • Muscle cramps;
  • Involuntary muscle contractions and tingling;
  • Numbness;
  • Cognitive problems;
  • Depression;
  • Anxiety;
  • Loss of appetite;
  • Headaches;
  • Abdominal pains;
  • Muscle weakness;
  • Tiredness;
  • Nausea and vomiting;
  • Worsened insulin resistance;
  • Irregular heart rhythm;
  • Apathy;
  • Metabolic syndrome;
  • Severe lack of energy;
  • Heart failure;
  • High blood pressure.

Low absorption of magnesium in the body is associated with low magnesium content diet, alcohol consumption, as a side effect of some medications or existing health conditions, such as heart diseases, diabetes, or cancer.

Magnesium-Rich Foods

Including food that contains high levels of magnesium on a daily basis is strongly recommended. Some excellent food-sources of magnesium include:

  • Dark green leafy greens (Spinach, Kale, Lettuce, Cabbage)
  • Beans; 
  • Fish; 
  • Whole grains; 
  • Nuts; 
  • Dark chocolate; 
  • Yogurt; 
  • Avocados; 
  • Bananas;
  • Almonds;
  • Peanuts;
  • Tuna;
  • Brown rice;
  • Chickpeas;
  • Lentils;
  • Cashews;
  • Broccoli;
  • Milk;
  • Dairy products.

Green leafy vegetables are an especially important part of a magnesium-rich diet since they are packed with a lot of other vitamins, minerals, and fiber. Including kale, spinach, collard greens, cabbage, watercress, romaine lettuce, or swiss chard in our meals has numerous health benefits, and also drastically reduces the risk of high blood pressure, mental problems, low energy, bad mood, obesity, etc.

Magnesium Supplements

According to the Office of Dietary Supplements (ODS), dietary magnesium intake has beneficial effects on overall health. More specifically, magnesium supplementation in the right doses has the following beneficial effects upon our health:

  • It prevents high blood pressure and heart diseases by lowering the blood pressure; 
  • It lowers the risk of developing type 2 diabetes by helping the body break down sugars, thus improving insulin sensitivity;
  • It prevents osteoporosis by improving bone health and bone mineral density;
  • It reduces the blood sugar levels even in people with normal glucose values;
  • It supports the muscle and nerve functions;
  • It alleviates migraine headaches;
  • It provides a steady rhythm of the heart. 

Magnesium supplements are typically administered to protect the patient against an excessive loss of magnesium due to various medical conditions. The daily recommended dietary allowance (RDA) of this mineral for an adult is 350 mg of magnesium in the USA, and 300 mg of magnesium in the EU. Assessment of the total serum magnesium concentration is the best way for determining the adequate magnesium intake for each individual. 

Magnesium Toxicity

There aren’t many side effects of taking too much magnesium, since the body will only absorb as much as it needs of this mineral. More than half of the magnesium quantities in our body is stored in the bones. 

Magnesium toxicity occurs rarely, but it’s not uncommon. It may result due to the accumulation of magnesium in extremely high doses, especially after excessive use of magnesium sulfate as a laxative in the form of Epsom salts.

Important: Please note that this magnesium fact sheet is for educational and informative purposes only. This list is not complete and many other drugs may interact with magnesium, including prescription and over-the-counter medicines, proton pump inhibitor (PPI) drugs, vitamins, and herbal products. We strongly advise that you seek medical advice from a qualified healthcare provider or trained health professionals before treating any medical problems or adding magnesium supplements to your diet.

How Dangerous Is Magnesium?

Due to its strong flame and volatile reactions with nitrogen, oxygen, and water, magnesium may pose a fire hazard. This substance may spontaneously ignite if it comes into contact with acids, air, or moisture. Namely, magnesium forms the highly flammable hydrogen gas in reactions with acids and water which can easily explode. The fumes of the flame produced by burning magnesium are also toxic.

Environmental Effects of Magnesium

Magnesium, as a part of various chemical compounds, has a significant role in environmental protection. When the industrial wastewaters are treated with dead-burned magnesia and caustic-calcined magnesia (both products of magnesia), they remove silica and the acidic heavy metals that form hydroxides from the waters by chemical precipitation.

Also, magnesium-rich compounds have high absorbing properties which enable these substances to remove sulfur dioxide from the industrial air emissions, as well as to remove the hazardous elements from the chemical spills.

Isotopes of Magnesium

There are 21 isotopes of magnesium, out of which 18 are radioactive. This chemical element naturally occurs in three forms: magnesium-24, magnesium-25, and magnesium-26 isotope. 

Having a half-life of 20.915 hours, 28Mg is the magnesium form with the longest life. On the other hand, 19Mg is the magnesium isotope with the shortest life. The heavier isotopes typically decay into aluminum (Al), while the lighter forms of magnesium decay to the element sodium (Na). 

Nuclide[2]ZNIsotopic mass (Da)[3]

[n 1]


[n 2]



[n 3]



[n 4]

Spin and


[n 5][n 2]

Natural abundance (mole fraction)
Normal proportionRange of variation
19Mg12719.03417(5)5(3) ps2p17Ne1/2−#  
20Mg12820.0187631(2)93(5) msβ+ (69.7%)20Na0+  
β+, p (30.3%)19Ne
21Mg12921.0117058(8)118.6(5) msβ+ (66.9%)21Na5/2+  
β+, p (32.6%)20Ne
β+, α (0.5%)17F
22Mg121021.9995707(3)3.8755(12) sβ+22Na0+  
23Mg121122.99412394(17)11.317(11) sβ+23Na3/2+  
26Mg[n 6]121425.98259297(3)Stable0+0.1101(3)0.10987–0.11030
27Mg121526.98434063(5)9.435(27) minβ27Al1/2+  
28Mg121627.9838766(21)20.915(9) hβ28Al0+  
29Mg121728.988617(12)1.30(12) sβ29Al3/2+  
30Mg121829.990463(4)313(4) msβ (99.94%)30Al0+  
β, n (0.06%)29Al
31Mg121930.996648(3)236(20) msβ (93.8%)31Al1/2(+)  
β, n (6.2%)30Al
32Mg122031.999110(4)86(5) msβ (94.5%)32Al0+  
β, n (5.5%)31Al
33Mg122133.005327(3)90.5(16) msβ (86%)33Al3/2−  
β, n (14%)32Al
34Mg122234.00894(3)20(10) msβ (70%)34Al0+  
β, n (30%)33Al
35Mg122335.01679(29)70(40) msβ, n (52%)34Al7/2−#  
β (48%)35Al
36Mg122436.02188(74)3.9(13) msβ36Al0+  
37Mg122537.03029(75)8(4) msβ37Al(3/2−)  
β, n36Al
38Mg122638.03658(54)#1# ms [>260 ns]  0+  
40Mg122840.05191(54)#1# msβ, n39Al0+  

Source: Wikipedia

List of Magnesium Compounds 

Magnesium typically adopts the oxidation state of +2 when it participates in a chemical compound. Magnesium salts can occur in the form of oxides, hydroxides, sulphates, carbonates, citrates, and trisilicates. 

This highly reactive element replaces hydrogen in water heated to the boiling temperature. By the method of thermal reduction of magnesium salts, many other compounds are produced as a result. For instance, when magnesium carbonate (magnesite, MgCO3) is exposed to temperatures ranging from 700°C to 1000°C, the chemical reaction produces magnesium oxide MgO and carbon dioxide CO2 (gas) as a result. 

The following is a list of the most commonly occurring magnesium compounds:

  • Magnesium Phosphate
  • Magnesium Sulfate Heptahydrate
  • Magnesium Chloride Hexahydrate
  • Magnesium Nitrite
  • Magnesium Citrate
  • Magnesium Ammonium Phosphate Hexahydrate
  • Magnesium Chlorate
  • Magnesium Dihydrogen Phosphate
  • Magnesium Hydrogen Carbonate
  • Magnesium Cyanide
  • Magnesium Hypophosphite
  • Magnesium Sulfate
  • Magnesium Hydroxide
  • Magnesium Nitrate
  • Magnesium Chloride
  • Magnesium Acetate
  • Magnesium Hypochlorite
  • Magnesium Phosphide
  • Magnesium Hydrogen Sulfate
  • Magnesium Sulfite
  • Magnesium Hydrogen Phosphate
  • Magnesium Hydrogen Sulfite
  • Magnesium Dichromate
  • Magnesium Iodate
  • Magnesium Permanganate
  • Magnesium Oxide
  • Magnesium Bromate
  • Magnesium Chlorite
  • Magnesium Nitride
  • Magnesium Iodide
  • Magnesium Oxalate
  • Magnesium Carbonate

5 Interesting Facts and Explanations

  1. Since the translucent crystals of the Epsom salts (hydrated magnesium sulphate) resemble snow by their physical appearance, this magnesium compound can be used for various fun art and craft projects
  2. Even a small amount of magnesium can prevent fatigue and alleviate stress.
  3. After the elements iron, oxygen and, silicon, magnesium is both the fourth most common element and the eighth most abundant chemical on our Planet. Magnesia, or magnesium oxide (MgO), occurs as the second most abundant compound in Earth’s crust.
  4. Magnesium produced from magnesium chloride enriched brine or seawater has fewer impurities than the magnesium substance obtained from the magnesium-rich mineral ores. 
  5. In nature, magnesium can often be found alongside the elements carbon, calcium, and oxygen.