Magnesium compounds

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Magnesium compounds are compounds formed by the element magnesium (Mg). These compounds are important to industry and biology, including magnesium carbonate, magnesium chloride, magnesium citrate, magnesium hydroxide (milk of magnesia), magnesium oxide, magnesium sulfate, and magnesium sulfate heptahydrate (Epsom salts).

Contents

Inorganic compounds

Hydrides, halides and oxo-halides

Magnesium hydride was first prepared in 1951 by the reaction between hydrogen and magnesium under high temperature, pressure and magnesium iodide as a catalyst. [1] It reacts with water to release hydrogen gas; it decomposes at 287 °C, 1 bar: [2]

MgH2 → Mg + H2

Magnesium can form compounds with the chemical formula MgX2 (X=F, Cl, Br, I) with halogens. Except for magnesium fluoride, the halides are easily soluble in water, but the solubility of magnesium fluoride is higher than that of other alkaline earth metal fluorides. High-purity magnesium fluoride is produced industrially by the reaction of magnesium sulfate and sodium fluoride, which sublimates at 1320 °C. Magnesium chloride is generally obtained by chlorination of magnesium oxide, or by reacting magnesium chloride hexahydrate with ammonium chloride under dry hydrogen chloride, and then thermally decomposing the resulting magnesium ammonium double salt. [3] Its hydrate will be hydrolyzed, making the solution acidic; direct heating of the hydrate will give the hydrolyzed product: [3] [4]

[Mg(H2O)6]2+ → [Mg(H2O)5(OH)]+ + H3O+ (decomposes in water)
MgCl2·nH2O → Mg(OH)Cl + HCl + (n-1)H2O (decomposes when heated)

Magnesium chloride is an ionic compound, which can be electrolysed in a molten state to form magnesium and chlorine gas. The properties of magnesium bromide and magnesium iodide are similar. [4] HMgX (X=Cl,Br,I) can be obtained by reacting the corresponding magnesium halide with magnesium hydride. [3]

Magnesium perchlorate is a white slid commonly used as a desiccant. Magnija perhlorats 02.jpg
Magnesium perchlorate is a white slid commonly used as a desiccant.

Magnesium hypochlorite and magnesium chlorite are unstable compounds, they are easy to hydrolyze, the former generates basic salt Mg(OCl)2·2Mg(OH)2 and the latter generates hydroxide Mg(OH)2; magnesium chlorate can be obtained by reacting magnesium carbonate with chloric acid and crystallizing hexahydrate from solution, which can also be obtained by reacting magnesium hydroxide with chlorine gas and extracted with acetone: [4]

6 Mg(OH)2 + 6 Cl2 → 5 MgCl2 + Mg(ClO3)2 + 6 H2O

Magnesium perchlorate is a white powder that is easily soluble in water, which can be obtained by the reaction of magnesium oxide and perchloric acid. The hexahydrate crystallizes from the solution, and then it is dried with phosphorus pentoxide in a vacuum at 200~250 °C to obtain the anhydrous form. It is a commonly used desiccant and can also be used as a Lewis acid or electrophile activator. [5] Magnesium perbromate can also crystallize out of the solution to form the hexahydrate, which can be heated to obtain anhydrous, and the anhydrous is further heated, and it decomposes into magnesium oxide, bromine and oxygen. [6]

Oxides and chalcogenides

Magnesium oxide is the end product of the thermal decomposition of some magnesium compounds and is usually prepared by igniting carbonates or hydroxides. Magnesium hydroxide is a strong electrolyte, which can be obtained by the reaction of a soluble magnesium salt and sodium hydroxide. Like magnesium oxide, it will generate a basic carbonate when placed in the air. [3] Magnesium sulfide can be produced by the reaction of magnesium and hydrogen sulfide, or by the reaction of magnesium sulfate and carbon disulfide at high temperature: [7]

Mg + H2S → MgS + H2
3 MgSO4 + 4 CS2 → 3 MgS + 4 COS + 4 SO2

It can be hydrolyzed to Mg(HS)2, and further hydrolyzed to Mg(OH)2 at higher temperatures. A solution of magnesium hydrosulfide can also be prepared by reacting hydrogen sulfide with magnesium oxide in suspension. [8] Magnesium polysulfides have been studied in magnesium-sulfur batteries. [9] Magnesium selenide is more reactive than zinc selenide and decomposes in humid air; [10] the properties of magnesium telluride and magnesium selenide are similar. [11]

Organic compounds

Grignard reagent

The name of the Grignard reagent comes from the French chemist Victor Grignard who discovered it. This type of organomagnesium compound has the general formula R–Mg–X, where R is a hydrocarbon group and X is a halogen. They are usually coordinated with solvent molecules. bit. Grignard reagents can be obtained by reacting magnesium with halogenated hydrocarbons in a solvent. Since there is an oxide film on the surface of magnesium, iodine is generally added to accelerate the reaction. [3] Grignard reagents are commonly used in organic synthesis to extend carbon chains: [12]

Grignard with carbonyl.png

Dihydrocarbylmagnesium

Dihydrocarbylmagnesium is an organic compound with R–Mg–R’, which can be prepared by the reaction of dihydrocarbylmercury and magnesium. [13] Their reactivity is similar to that of Grignard reagents, and they can react with oxygen, water, and ammonia. [14]

Magnesium anthracene is the product obtained from the reaction of magnesium and anthracene in tetrahydrofuran, which can be used to provide C14H102− carbanions, which react with electrophiles to obtain di-derivatives of hydrogen anthracene. [15]

Applications

Magnesium compounds, primarily magnesium oxide (MgO), are used as a refractory material in furnace linings for producing iron, steel, nonferrous metals, glass, and cement. Magnesium oxide and other magnesium compounds are also used in the agricultural, chemical, and construction industries. Magnesium oxide from calcination is used as an electrical insulator in fire-resistant cables. [16] Other applications include:

See also

Related Research Articles

<span class="mw-page-title-main">Magnesium</span> Chemical element, symbol Mg and atomic number 12

Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals it occurs naturally only in combination with other elements and it almost always has an oxidation state of +2. It reacts readily with air to form a thin passivation coating of magnesium oxide that inhibits further corrosion of the metal. The free metal burns with a brilliant-white light. The metal is obtained mainly by electrolysis of magnesium salts obtained from brine. It is less dense than aluminium and is used primarily as a component in strong and lightweight alloys that contain aluminium.

<span class="mw-page-title-main">Alkaline earth metal</span> Group of chemical elements

The alkaline earth metals are six chemical elements in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). The elements have very similar properties: they are all shiny, silvery-white, somewhat reactive metals at standard temperature and pressure.

<span class="mw-page-title-main">Haloalkane</span> Group of chemical compounds derived from alkanes containing one or more halogens

The haloalkanes are alkanes containing one or more halogen substituents. They are a subset of the general class of halocarbons, although the distinction is not often made. Haloalkanes are widely used commercially. They are used as flame retardants, fire extinguishants, refrigerants, propellants, solvents, and pharmaceuticals. Subsequent to the widespread use in commerce, many halocarbons have also been shown to be serious pollutants and toxins. For example, the chlorofluorocarbons have been shown to lead to ozone depletion. Methyl bromide is a controversial fumigant. Only haloalkanes that contain chlorine, bromine, and iodine are a threat to the ozone layer, but fluorinated volatile haloalkanes in theory may have activity as greenhouse gases. Methyl iodide, a naturally occurring substance, however, does not have ozone-depleting properties and the United States Environmental Protection Agency has designated the compound a non-ozone layer depleter. For more information, see Halomethane. Haloalkane or alkyl halides are the compounds which have the general formula "RX" where R is an alkyl or substituted alkyl group and X is a halogen.

<span class="mw-page-title-main">Magnesium carbonate</span> Chemical compound

Magnesium carbonate, MgCO3, is an inorganic salt that is a colourless or white solid. Several hydrated and basic forms of magnesium carbonate also exist as minerals.

<span class="mw-page-title-main">Magnesium chloride</span> Inorganic salt: MgCl2 and its hydrates

Magnesium chloride is an inorganic compound with the formula MgCl2. It forms hydrates MgCl2·nH2O, where n can range from 1 to 12. These salts are colorless or white solids that are highly soluble in water. These compounds and their solutions, both of which occur in nature, have a variety of practical uses. Anhydrous magnesium chloride is the principal precursor to magnesium metal, which is produced on a large scale. Hydrated magnesium chloride is the form most readily available.

<span class="mw-page-title-main">Aluminium chloride</span> Chemical compound

Aluminium chloride, also known as aluminium trichloride, is an inorganic compound with the formula AlCl3. It forms a hexahydrate with the formula [Al(H2O)6]Cl3, containing six water molecules of hydration. Both the anhydrous form and the hexahydrate are colourless crystals, but samples are often contaminated with iron(III) chloride, giving them a yellow colour.

A direct combination reaction (also known as a synthesis reaction) is a reaction where two or more elements or compounds (reactants) combine to form a single compound (product). Such reactions are represented by equations of the following form: X + Y → XY (A+B → AB). The combination of two or more elements to form one compound is called a combination reaction. In other words, when two or more elements or compounds react so as to form one single compound, then the chemical reaction that takes place is called a combination reaction. | a)- Between elements | C + O2 → CO2 | Carbon completely burnt in oxygen yields carbon dioxide |- | b) Between compounds | CaO + H2O → Ca(OH)2 | Calcium oxide (lime) combined with water gives calcium hydroxide (slaked lime) |- | c) Between elements and compounds | 2CO + O2 → 2CO2 | Oxygen combines with carbon monoxide,And carbon dioxide is formed. |}

<span class="mw-page-title-main">Hexafluorosilicic acid</span> Octahedric silicon compound

Hexafluorosilicic acid is an inorganic compound with the chemical formula H
2SiF
6. Aqueous solutions of hexafluorosilicic acid consist of salts of the cation and hexafluorosilicate anion. These salts and their aqueous solutions are colorless.

<span class="mw-page-title-main">Grignard reagent</span> Organometallic compounds used in organic synthesis

A Grignard reagent or Grignard compound is a chemical compound with the general formula R−Mg−X, where X is a halogen and R is an organic group, normally an alkyl or aryl. Two typical examples are methylmagnesium chloride Cl−Mg−CH3 and phenylmagnesium bromide (C6H5)−Mg−Br. They are a subclass of the organomagnesium compounds.

<span class="mw-page-title-main">Magnesium iodide</span> Chemical compound

Magnesium iodide is an inorganic compound with the chemical formula MgI2. It forms various hydrates MgI2·xH2O. Magnesium iodide is a salt of magnesium and hydrogen iodide. These salts are typical ionic halides, being highly soluble in water.

<span class="mw-page-title-main">Lead compounds</span> Type of compound

Compounds of lead exist with lead in two main oxidation states: +2 and +4. The former is more common. Inorganic lead(IV) compounds are typically strong oxidants or exist only in highly acidic solutions.

<span class="mw-page-title-main">Sodium bifluoride</span> Chemical compound

Sodium bifluoride is the inorganic compound with the formula Na[HF2]. It is a salt of sodium cation and bifluoride anion. It is a white, water-soluble solid that decomposes upon heating. Sodium bifluoride is non-flammable, hygroscopic, and has a pungent smell. Sodium bifluoride has a number of applications in industry.

Magnesium hydroxychloride is the traditional term for several chemical compounds of magnesium, chlorine, oxygen, and hydrogen whose general formula xMgO·yMgCl
2·zH
2O, for various values of x, y, and z; or, equivalently, Mg
x+y(OH)
2xCl
2y(H
2O)
z−x. The simple chemical formula that is often used is MgClOH, which appears in high school subject, for example.Other names for this class are magnesium chloride hydroxide, magnesium oxychloride, and basic magnesium chloride. Some of these compounds are major components of Sorel cement.

<span class="mw-page-title-main">Aluminium compounds</span>

Aluminium (or aluminum) combines characteristics of pre- and post-transition metals. Since it has few available electrons for metallic bonding, like its heavier group 13 congeners, it has the characteristic physical properties of a post-transition metal, with longer-than-expected interatomic distances. Furthermore, as Al3+ is a small and highly charged cation, it is strongly polarizing and aluminium compounds tend towards covalency; this behaviour is similar to that of beryllium (Be2+), an example of a diagonal relationship. However, unlike all other post-transition metals, the underlying core under aluminium's valence shell is that of the preceding noble gas, whereas for gallium and indium it is that of the preceding noble gas plus a filled d-subshell, and for thallium and nihonium it is that of the preceding noble gas plus filled d- and f-subshells. Hence, aluminium does not suffer the effects of incomplete shielding of valence electrons by inner electrons from the nucleus that its heavier congeners do. Aluminium's electropositive behavior, high affinity for oxygen, and highly negative standard electrode potential are all more similar to those of scandium, yttrium, lanthanum, and actinium, which have ds2 configurations of three valence electrons outside a noble gas core: aluminium is the most electropositive metal in its group. Aluminium also bears minor similarities to the metalloid boron in the same group; AlX3 compounds are valence isoelectronic to BX3 compounds (they have the same valence electronic structure), and both behave as Lewis acids and readily form adducts. Additionally, one of the main motifs of boron chemistry is regular icosahedral structures, and aluminium forms an important part of many icosahedral quasicrystal alloys, including the Al–Zn–Mg class.

An yttrium compound is a chemical compound containing yttrium. Among these compounds, yttrium generally has a +3 valence. The solubility properties of yttrium compounds are similar to those of the lanthanides. For example oxalates and carbonates are hardly soluble in water, but soluble in excess oxalate or carbonate solutions as complexes are formed. Sulfates and double sulfates are generally soluble. They resemble the "yttrium group" of heavy lanthanide elements.

<span class="mw-page-title-main">Europium compounds</span> Compounds with at least one europium atom

Europium compounds are compounds formed by the lanthanide metal europium (Eu). In these compounds, europium generally exhibits the +3 oxidation state, such as EuCl3, Eu(NO3)3 and Eu(CH3COO)3. Compounds with europium in the +2 oxidation state are also known. The +2 ion of europium is the most stable divalent ion of lanthanide metals in aqueous solution. Many europium compounds fluoresce under ultraviolet light due to the excitation of electrons to higher energy levels. Lipophilic europium complexes often feature acetylacetonate-like ligands, e.g., Eufod.

Cobalt compounds are chemical compounds formed by cobalt with other elements.

Neptunium compounds are compounds containg the element neptunium (Np). Neptunium has five ionic oxidation states ranging from +3 to +7 when forming chemical compounds, which can be simultaneously observed in solutions. It is the heaviest actinide that can lose all its valence electrons in a stable compound. The most stable state in solution is +5, but the valence +4 is preferred in solid neptunium compounds. Neptunium metal is very reactive. Ions of neptunium are prone to hydrolysis and formation of coordination compounds.

Americium compounds are compounds containing the element americium (Am). These compounds can form in the +2, +3, and +4, although the +3 oxidation state is the most common. The +5, +6 and +7 oxidation states have also been reported.

References

  1. ↑ Egon Wiberg; Heinz Goeltzer; Richard Bauer (1951). "Synthese von Magnesiumhydrid aus den Elementen (Synthesis of Magnesium Hydride from the Elements)" (PDF). Zeitschrift für Naturforschung B. 6b: 394. Archived from the original (PDF) on 2020-09-20. Retrieved 2021-12-06.
  2. ↑ McAuliffe, T. R. (1980). Hydrogen and Energy (illustrated ed.). Springer. p. 65. ISBN   978-1-349-02635-7. Archived from the original on 2022-03-25. Retrieved 2021-12-06. Extract of page 65 Archived 2021-12-06 at the Wayback Machine
  3. 1 2 3 4 5 无机化学丛书. 第二卷. 铍 碱土金属 硼 铝 镓分族. 科学出版社. pp 154
  4. 1 2 3 R. C. Ropp. Encyclopedia of the Alkaline Earth Compounds, Elsevier. ISBN 9780444595508.
  5. ↑ Chakraborti, Asit K.; Chankeshwara, Sunay V. (2009-03-15), "Magnesium Perchlorate", Encyclopedia of Reagents for Organic Synthesis, Chichester, UK: John Wiley & Sons, Ltd, doi:10.1002/047084289x.rn01002, ISBN   978-0471936237
  6. ↑ Isupov, V. K.; Gavrilov, V. V.; Kirin, I. S. Thermal decomposition of magnesium, calcium, strontium and barium perbromates(in Russian). Zhurnal Neorganicheskoi Khimii, 1977. 22 (9): 2592-2594. ISSN   0044-457X.
  7. ↑ Marianne Baudler (1978). Handbuch der präparativen anorganischen Chemie Bd. 2. / Unter Mitarb. von M. Baudler ... (3., umgearb. Aufl ed.). Stuttgart. ISBN   978-3-432-87813-3. OCLC   310719490.{{cite book}}: CS1 maint: location missing publisher (link)
  8. ↑ Edward Divers; Tetsukichi Shimidzu (1884). "LVII.—Magnesium hydrosulphide solution, and its use in chemicolegal cases as a source of hydrogen sulphide". Journal of the Chemical Society, Transactions. 45: 699–702. doi:10.1039/CT8844500699. ISSN   0368-1645 . Retrieved 2021-12-10.
  9. ↑ Divyamahalakshmi Muthuraj; Madhu Pandey; Murali Krishna; Arnab Ghosh; Raja Sen; Priya Johari; Sagar Mitra (February 2021). "Magnesium polysulfide catholyte (MgSx): Synthesis, electrochemical and computational study for magnesium-sulfur battery application". Journal of Power Sources. 486: 229326. Bibcode:2021JPS...48629326M. doi:10.1016/j.jpowsour.2020.229326. S2CID   233781012 . Retrieved 2021-12-10.
  10. ↑ Moser, L.; Doctor, E. Preparation of hydrogen selenide from metallic selenides. Zeitschrift fuer Anorganische und Allgemeine Chemie, 1921. 118: 284-292. ISSN   0044-2313.
  11. ↑ Moser, L.; Ertl, K. The preparation of hydrogen telluride from metallic tellurides. Zeitschrift fuer Anorganische und Allgemeine Chemie, 1921. 118: 269-283. ISSN   0044-2313.
  12. ↑ Henry Gilman and R. H. Kirby (1941). "Butyric acid, α-methyl-". Organic Syntheses .; Collective Volume, vol. 1, p. 361
  13. ↑ 宋礼成，王佰全. 金属有机化学原理及应用. 高等教育出版社, 2012.10. pp 104-118. 镁有机化合物. ISBN 978-7-04-035161-3
  14. ↑ Schlenk, Wilh, Jr. Magnesium dialkyls and magnesium diaryls. Berichte der Deutschen Chemischen Gesellschaft [Abteilung] B: Abhandlungen, 1931. 64B: 736-739. ISSN   0365-9488.
  15. ↑ Borislav Bogdanovic (1988-07-01). "Magnesium anthracene systems and their application in synthesis and catalysis". Accounts of Chemical Research. 21 (7): 261–267. doi:10.1021/ar00151a002. ISSN   0001-4842. Archived from the original on 2021-12-06. Retrieved 2021-12-10.
  16. ↑ Linsley, Trevor (2011). "Properties of conductors and insulators". Basic Electrical Installation Work. Taylor & Francis. p. 362. ISBN   978-0080966281.

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