The magnesium It is an alkaline earth metal that belongs to group 2 of the periodic table. Its atomic number is 12 and it is represented by the chemical symbol Mg. It is the eighth most abundant element in the earth's crust, about 2.5% of it.
This metal, like its congeners and the alkali metals, is not found in nature in its native state, but combines with other elements to form numerous compounds present in rocks, seawater and in brine..
Magnesium is part of minerals such as dolomite (calcium and magnesium carbonate), magnesite (magnesium carbonate), carnalite (magnesium and potassium chloride hexahydrate), brucite (magnesium hydroxide) and in silicates such as talc and olivine.
Its richest natural source for its extension is the sea, which has an abundance of 0.13%, although the Great Salt Lake (1.1%) and the Dead Sea (3.4%) have a higher concentration of magnesium. There are brines with a high content of it, which is concentrated by evaporation.
The name magnesium probably derives from magnesite, found in Magnesia, in the region of Thessaly, ancient Region of Greece. Although, it has been pointed out that magnetite and manganese were found in the same region.
Magnesium reacts strongly with oxygen at temperatures above 645 ° C. Meanwhile, magnesium powder burns in dry air, emitting an intense white light. For this reason, it was used as a light source in photography. Currently, this property is still used in pyrotechnics.
It is an essential element for living beings. It is known to be a cofactor for more than 300 enzymes, including several glycolysis enzymes. This is a vital process for living beings due to its relationship with the production of ATP, the main source of cellular energy..
Likewise, it is part of a complex similar to the heme group of hemoglobin, present in chlorophyll. This is a pigment involved in photosynthesis..
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Joseph Black, a Scottish chemist, in 1755 recognized it as an element, demonstrating experimentally that it was different from calcium, a metal with which they confused it.
In this regard, Black wrote: "We already see by experiment that magnesia alba (magnesium carbonate) is a compound of a peculiar earth and fixed air".
In 1808, Sir Humprey Davy managed to isolate it using electrolysis to produce an amalgam of magnesium and mercury. It did this by electrolyzing its wet sulfate salt using mercury as the cathode. Subsequently, it evaporated the mercury from the malgam by heating, leaving the magnesium residue.
A. Bussy, a French scientist, managed to produce the first metallic magnesium in 1833. To do this, Bussy produced the reduction of molten magnesium chloride with metallic potassium.
In 1833, the British scientist Michael Faraday used for the first time the electrolysis of magnesium chloride for the isolation of this metal..
In 1886, the German company Aluminum und Magnesiumfabrik Hemelingen used the electrolysis of carnalite (MgCltwoKCl 6HtwoO) melted to produce magnesium.
Hemelingen, associated with the Farbe Industrial Complex (IG Farben), succeeded in developing a technique to produce large amounts of molten magnesium chloride for electrolysis for the production of magnesium and chlorine..
During World War II, the Dow Chemical Company (USA) and Magnesium Elektron LTD (UK) began the electrolytic reduction of seawater; pumped from Galveston Bay, Texas and in the North Sea to Hartlepool, England, for magnesium production.
At the same time, Ontario (Canada) creates a technique to produce it based on the process of L. M. Pidgeon. The technique consists of the thermal reduction of magnesium oxide with silicates in externally fired retorts..
Magnesium crystallizes in a compact hexagonal structure, where each of its atoms is surrounded by twelve neighbors. This makes it more dense than other metals, such as lithium or sodium..
Its electron configuration is [Ne] 3stwo, with two valence electrons and ten inner shell electrons. By having an additional electron compared to sodium, its metallic bond becomes stronger.
This is because the atom is smaller and its nucleus has one more proton; therefore they exert a greater attraction effect on the electrons of neighboring atoms, which contracts the distances between them. Also, since there are two electrons, the resulting 3s band is full, and it is able to feel even more the attraction of the nuclei.
Then, the Mg atoms end up laying a dense hexagonal crystal with a strong metallic bond. This explains its melting point much higher (650 ºC) than that of sodium (98 ºC).
All the 3s orbitals of all the atoms and their twelve neighbors overlap in all directions within the crystal, and the two electrons leave as two others come; so on, without the Mg cations being able to originatetwo+.
Magnesium can lose two electrons when it forms compounds and become the Mg cation.two+, which is isoelectronic to the noble gas neon. When considering its presence in any compound, the oxidation number of magnesium is +2.
On the other hand, and although less common, the Mg cation can be formed+, which has only lost one of its two electrons and is isoelectronic to sodium. When its presence in a compound is assumed, then magnesium is said to have an oxidation number of +1.
Brilliant white solid in its pure state, before oxidizing or reacting with humid air.
24.304 g / mol.
650 ºC.
1,091 ºC.
1,738 g / cm3 at room temperature. And 1,584 g / cm3 at melting temperature; that is, the liquid phase is less dense than the solid, as is the case with the vast majority of compounds or substances.
848 kJ / mol.
128 kJ / mol.
24.869 J / (mol K).
At 701 K: 1 Pa; that is, its vapor pressure is very low.
1.31 on the Pauling scale.
First ionization level: 1,737.2 kJ / mol (Mg+ gaseous)
Second ionization level: 1,450.7 kJ / mol (Mgtwo+ gaseous, and requires less energy)
Third level of ionization: 7,732.7 kJ / mol (Mg3+ gaseous, and requires a lot of energy).
160 pm.
141 ± 17 pm
13.97 cm3/ mol.
24.8 µm / m K at 25 ºC.
156 W / m K.
43.9 nΩ · m at 20 ºC.
22.4 × 106 S cm3.
2.5 on the Mohs scale.
Metallic magnesium has no other attributed names. Its compounds, since it is considered that in the majority they have an oxidation number of +2, are mentioned using the stock nomenclature without the need to express said number in parentheses..
For example, MgO is magnesium oxide and not magnesium (II) oxide. According to the systematic nomenclature, the previous compound is: magnesium monoxide and not monomagnesium monoxide.
On the side of the traditional nomenclature, the same thing happens as with the stock nomenclature: the names of the compounds end in the same way; that is, with the suffix -ico. Thus, MgO is magnesium oxide, according to this nomenclature.
Otherwise, the other compounds may or may not have common or mineralogical names, or consist of organic molecules (organomagnesium compounds), whose nomenclature depends on the molecular structure and the alkyl (R) or aryl (Ar) substituents..
Regarding organomagnesium compounds, almost all are Grignard reagents with the general formula RMgX. For example, the BrMgCH3 is methyl magnesium bromide. Note that the nomenclature does not seem so complicated in a first contact .
Magnesium is used in alloys because it is a light metal, being used mainly in alloys with aluminum, which improves the mechanical characteristics of this metal. It has also been used in alloys with iron.
However, its use in alloys has declined due to its tendency to corrode at high temperatures..
Due to its reactivity it is not found in the earth's crust in a native or elemental form. Rather, it is part of numerous chemical compounds, which in turn are located in around 60 known minerals..
Among the most common minerals of magnesium are:
-Dolomite, a carbonate of calcium and magnesium, MgCO3·Thief3
-Magnesite, a magnesium carbonate, CaCO3
-Brucite, a magnesium hydroxide, Mg (OH)two
-carnalite, a magnesium potassium chloride, MgCltwoKClHtwoOR.
Also, it can be in the form of other minerals such as:
-Kieserite, a magnesium sulfate, MgSO4HtwoOR
-Forsterite, a magnesium silicate, MgSiO4
-Chrysotile or asbestos, other magnesium silicate, Mg3YestwoOR5(OH)4
-Talc, Mg3Yes14OR110(OH)two.
Magnesium is found in nature as a combination of three natural isotopes: 24Mg, with 79% abundance; 25Mg, with 11% abundance; and the 26Mg, with 10% abundance. In addition, there are 19 artificial radioactive isotopes.
Magnesium is an essential element for all living things. Humans have a daily intake of 300 - 400 mg of magnesium. Its body content is comprised between 22 and 26 g, in an adult human being, concentrated mainly in the bone skeleton (60%).
Glycolysis is a sequence of reactions in which glucose is transformed into pyruvic acid, with a net production of 2 ATP molecules. Pyruvate kinase, hexokinase and phosphofruct kinase are enzymes, among others, of glycolysis that use Mg as an activator.
DNA is made up of two nucleotide chains that have negatively charged phosphate groups in their structure; therefore, the DNA strands undergo electrostatic repulsion. Na ions+, K+ and Mgtwo+, neutralize negative charges, preventing chain dissociation.
The ATP molecule has phosphate groups with negatively charged oxygen atoms. An electrical repulsion occurs between neighboring oxygen atoms that could cleave the ATP molecule.
This does not happen because magnesium interacts with neighboring oxygen atoms, forming a chelate. ATP-Mg is said to be the active form of ATP.
Magnesium is essential for photosynthesis, a central process in the use of energy by plants. It is part of chlorophyll, which has a structure similar to the heme group of hemoglobin in its interior; but with a magnesium atom in the center instead of an iron atom.
Chlorophyll absorbs light energy and uses it in photosynthesis to convert carbon dioxide and water into glucose and oxygen. Glucose and oxygen are subsequently used in energy production.
A decrease in plasma magnesium concentration is associated with muscle spasms; cardiovascular diseases, such as hypertension; diabetes, osteoporosis and other diseases.
The magnesium ion is involved in regulating the functioning of calcium channels in nerve cells. At high concentrations it blocks the calcium channel. On the contrary, a decrease in calcium produces an activation of the nerve by allowing the entry of calcium into the cells..
This would explain the spasm and contraction of muscle cells in the walls of major blood vessels..
Magnesium is not found in nature in an elemental state, but is part of approximately 60 minerals and numerous compounds, located in the sea, rocks and brines.
The sea has a magnesium concentration of 0.13%. Due to its size, the sea is the world's main magnesium reservoir. Other magnesium reservoirs are the Great Salt Lake (USA), with a magnesium concentration of 1.1%, and the Dead Sea, with a concentration of 3.4%.
Magnesium minerals, dolomite and magnesite, are extracted from its veins using traditional mining methods. Meanwhile, in carnalite solutions are used that allow the other salts to rise to the surface, keeping the carnalite in the background..
Magnesium-containing brines are concentrated in ponds using solar heating.
Magnesium is obtained by two methods: electrolysis and thermal reduction (Pidgeon process).
Molten salts containing either anhydrous magnesium chloride, partially dehydrated anhydrous magnesium chloride, or the mineral anhydrous carnalite are used in the electrolysis processes. In some circumstances, to avoid contamination of natural carnalite, artificial one is used.
Magnesium chloride can also be obtained by following the procedure designed by the Dow company. The water is mixed in a flocculator with the mineral slightly calcined dolomite.
The magnesium chloride present in the mixture is transformed into Mg (OH)two by the addition of calcium hydroxide, according to the following reaction:
MgCltwo + Ca (OH)two → Mg (OH)two + CaCltwo
The magnesium hydroxide precipitates is treated with hydrochloric acid, producing magnesium chloride and water, according to the outlined chemical reaction:
Mg (OH)two + 2 HCl → MgCltwo + 2 htwoOR
Then, the magnesium chloride is subjected to a dehydration process until it reaches 25% hydration, completing the dehydration during the smelting process. The electrolysis is carried out at a temperature that varies between 680 to 750 ºC..
MgCltwo → Mg + Cltwo
Diatomic chlorine is generated at the anode and molten magnesium floats to the top of the salts, where it is collected..
The reaction occurs at a temperature of 1200 ºC and a low pressure of 13 Pa. The magnesium crystals are removed from the condensers. The slag produced is collected from the bottom of the retorts.
2 CaO + 2 MgO + Si → 2 Mg (gas) + CatwoYes4 (human waste)
Calcium and magnesium oxides are produced by the calcination of calcium and magnesium carbonates present in dolomite.
Magnesium reacts vigorously with acids, especially oxacids. Its reaction with nitric acid produces magnesium nitrate, Mg (NO3)two. Similarly, it reacts with hydrochloric acid to produce magnesium chloride and hydrogen gas..
Magnesium does not react with alkalis, such as sodium hydroxide. At room temperature it is covered with a layer of magnesium oxide, insoluble in water, which protects it from corrosion.
It forms chemical compounds, among other elements, with chlorine, oxygen, nitrogen and sulfur. It is highly reactive with oxygen at high temperatures.
Magnesium alloys have been used in airplanes and automobiles. The latter have as a requirement for the control of polluting gas emissions, a reduction in the weight of motor vehicles.
Magnesium applications are based on its low weight, high strength and ease of making alloys. Applications include hand tools, sporting goods, cameras, home appliances, luggage frames, auto parts, items for the aerospace industry.
Magnesium alloys are also used in the manufacture of aircraft, rockets and space satellites, as well as in photo-etching for producing a fast and controlled engraving..
Magnesium is added in small amounts to cast white iron, which improves its strength and malleability. In addition, magnesium mixed with lime is injected into liquid blast furnace iron, improving the mechanical properties of the steel..
Magnesium is involved in the production of titanium, uranium and hafnium. Acts as a reducing agent on titanium tetrachloride, in the Kroll process, to originate titanium.
Magnesium is used in a dry cell, acting as the anode and silver chloride as the cathode. When magnesium comes into electrical contact with steel in the presence of water, it sacrificially corrodes, leaving the steel intact..
This type of steel protection is present in ships, storage tanks, water heaters, bridge structures, etc..
Magnesium in powder or strip form burns, emitting a very intense white light. This property has been used in military pyrotechnics to produce fires or lighting by flares..
Its finely divided solid has been used as a fuel component, especially in solid rocket propellants..
It is used as a thermal insulator for boilers and pipes. Being hygroscopic and soluble in water, it is used to prevent common salt from compacting in salt shakers and not flowing properly during food seasoning..
It has application as a fire retardant. Dissolved in water, it forms the well-known milk of magnesia, a whitish suspension that has been used as an antacid and laxative..
It is used in the manufacture of high-strength floor cement, as well as an additive in the manufacture of textiles. In addition, it is used as a flocculant in soy milk for the production of tofu..
It is used in the manufacture of refractory bricks to resist high temperatures and as a thermal and electrical insulator. It is also used as a laxative and antacid.
It is used industrially to make cement and fertilizers, tanning and dyeing. It is also a desiccant. Epsom salt, MgSO47HtwoOr, it is used as a purgative.
It is taken as the least hardness standard (1) on the Mohs scale. It serves as a filler in the manufacture of paper and cardboard, as well as preventing irritation and hydration of the skin. It is used in the manufacture of heat resistant materials and as the base of many powders used in cosmetics.
It has been used as a thermal insulator and in the construction industry for the manufacture of ceilings. Currently, it is not used because of its lung cancer fibers.
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