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Magnesium carbonate (archaic name magnesia alba), is an inorganic salt that is a colourless or white solid.
Several hydrated and basic forms of magnesium carbonate also exist as minerals.
CAS: 13717-00-5
MF: CH2O3.Mg
MW: 86.33
EINECS: 208-915-9
Mol File: 13717-00-5.mol
The most common magnesium carbonate forms are the anhydrous salt called magnesite (MgCO3), and the di, tri, and pentahydrates known as barringtonite (MgCO3·2H2O), nesquehonite (MgCO3·3H2O), and lansfordite (MgCO3·5H2O), respectively.
Some basic forms such as artinite (Mg2CO3(OH)2·3H2O), hydromagnesite (Mg5(CO3)4(OH)2·4H2O), and dypingite (Mg5(CO3)4(OH)2·5H2O) also occur as minerals.
All of those minerals are colourless or white.
Magnesite consists of colourless or white trigonal crystals.
The anhydrous salt is practically insoluble in water, acetone, and ammonia.
All forms of magnesium carbonate react with acids. Magnesite crystallizes in the calcite structure wherein Mg2+ is surrounded by six oxygen atoms.
The dihydrate has a triclinic structure, while the trihydrate has a monoclinic structure.
References to "light" and "heavy" magnesium carbonates actually refer to the magnesium hydroxy carbonates hydromagnesite and dypingite, respectively.
The "light" form is precipitated from magnesium solutions using alkali carbonate at "normal temperatures" while the "heavy" may be produced from boiling concentrated solutions followed by precipitation to dryness, washing of the precipitate, and drying at 100 C.
Chemical Properties
Magnesium carbonate, MgC03, is a light, bulky white powder, very slightly soluble in water,loses CO2 even on gentle heating.
Magnesium carbonate is used extensively in the manufacture of food products, pharmaceuticals, cosmetics, and magnesium salts.
Occurrence and Uses Magnesium carbonate occurs in nature in several minerals as hydrated, basic and double salts, as shown above.
The two principal minerals are magnesite, MgCO3 and dolomite, a double salt, CaCO3•MgCO3.
Both minerals are used as source materials in the production of magnesium metal.
Also, they are calcined to produce basic refractory bricks.
Other applications of magnesium carbonate are in flooring, fireproofing and fire-extinguishing compositions; as a filler material and smoke suppressant in plastics; as a reinforcing agent in neoprene rubber; as a drying agent and for color retention in foods; in cosmetics; in dusting powder; and in toothpaste.
The high purity magnesium carbonate is used as an antacid in medicine; and as an additive to table salt.
Another important application of magnesium carbonate is as a starting material in producing a number of magnesium compounds.
Synonyms:
Magnesıum Carbonate Basıc Hydrate; magnesıte; magnesıa 81010; magnesıa 81811;maggran(r) Mc;maggran(r) Mcplus;magnesıum Carbonate Hydrated Basıc;magnesıum Carbonate 40.0-43.50%(base On Mgo) Usp-24 Versıon
Melting point :2200 °C
density : 3.001 g/cm3
storage temp. :Hygroscopic, Room Temperature, under inert atmosphere
form : Solid
color : White to Off-White
Solubility Product Constant (Ksp) pKsp: 5.17
Stability:Hygroscopic
InChI InChI= 1S/CH2O3.Mg/c2-1(3)4;/h(H2,2,3,4);/q;+2/p-2
InChIKey:ZLNQQNXFFQJAID-UHFFFAOYSA-L
Preparation
Magnesium carbonate is obtained mainly by mining its natural mineral magnesite.
The trihydrate salt, MgCO3•3H2O, is prepared by mixing solutions of magnesium and carbonate ions in the presence of carbon dioxide.
Alternatively, it may be produced by carbonation of a magnesium hydroxide slurry with carbon dioxide under pressure (3.5 to 5 atm) and at a temperature below 50°C which yields soluble magnesium bicarbonate:
Mg(OH)2 + 2CO2 → Mg(HCO3)2
The solution is filtered to remove impurities and the filtrate is subjected to vacuum or aeration to yield insoluble magnesium carbonate as a hydrated salt:
Mg2 + 2HCO3¯ → MgCO3 + CO2 + H2O
Under ordinary conditions, anhydrous magnesium carbonate cannot be prepared in aqueous systems.
The anhydrous salt, however, can be made under very high partial pressures of carbon dioxide.
Basic magnesium carbonate occurs in nature as the mineral hydromagnesite.
The basic salt is obtained by mining the ore followed by purification.
The basic carbonates also can be made by drying the magnesium carbonate trihydrate at about 100°C.
Alternatively Magnesium carbonate can be prepared by simply boiling a solution of magnesium bicarbonate.
The bicarbonate is obtained by carbonation of a magnesium hydroxide slurry below 50°C and under a CO2 partial pressure of 3.5 to 5 atm.
Composition of the basic carbonate produced by the above methods is 4MgCO3 •Mg(OH)2•4H2O.
Another basic salt, MgCO3•Mg(OH)3•3H2O is precipitated when magnesium salt solution is treated with sodium carbonate solution.
The reactions probably are:
CO32– + H2O → HCO3¯ + OH¯
2Mg2+ + CO32– + 2OH¯ → MgCO3•Mg(OH)2
Description
Magnesium carbonate has the molecular formula of MgCO3 and the molecular weight of 84.3145 g/mol.
For the most part,Mg2+ forms several hydrated and basic carbonates that are stable and occur in nature.
The calcite structure of magnesium carbonate has the form wherein Mg2+ is surrounded by six O2- atoms.
The dihydrate composition has a triclinic structure, while the trihydrate has a monoclinic structure.
References to “light” and “heavy” magnesium carbonates actually refer to the magnesium hydroxycarbonates.
A space-filling structure of the anhydrous salt is seen in the above diagram where the triangular CO3 2- groups are clearly visible.
The term magnesium carbonate is generally reserved for the synthetic, pure variety.
The naturally occurring material is called magnesite.
Chemical Properties
Light, bulky, white powder.
Soluble in acids; very slightly soluble in water; insoluble in alcohol.
Noncombustible.
Chemical Properties
At room temperature, linolenic acid is a colorless liquid; soluble in most organic solvents; insoluble in water.
Combustible.
Uses
Magnesium Carbonate is an anticaking agent and general purpose food additive.
Magnesium carbonate is practically insoluble in water but is more soluble in water containing carbon dioxide.
Magnesium carbonate imparts a slightly alkaline reaction to the water.
Magnesium carbonate is used as an alkali in sour cream, butter, and canned peas.
Magnesium carbonate is used as an anticaking agent in table salt and dry mixes.
Magnesium carbonate assists in providing clarity in algin gels and functions as a filler in dental impression materials.
Magnesium salts, heat insulation and refractory, rubber reinforcing agent, inks, glass, pharmaceuticals, dentifrice and cosmetics, free-running table salts, antacid, making magnesium citrate, filtering medium. In foods as drying agent, color retention agent, anticaking agent, carrier.
Magnesium carbonate (MgCO3) is found in a mixture of natural minerals.
Magnesium carbonate can also be produced in several ways, including pumping carbon dioxide through magnesium oxide or magnesium hydroxide.
Magnesium carbonate is used in pharmaceuticals such as magnesium citrate and as a desiccant to keep hydroscopic products from caking (table salt) and to strengthen rubber and produce dyes, inks, and cosmetics.
Medical Uses
Magnesium carbonate is a laxative to loosen the bowels.
In addition, high purity magnesium carbonate is used as an antacid and as an additive in table salt to keep it free flowing.
Magnesium carbonate can do this because it does not dissolve in water, only in acid, where Magnesium carbonate will effervesce (bubble).
Raw materials
Sodium carbonate-->Magnesium chloride hexahydrate-->Magnesium chloride-->Dolomite (CaMg(CO3)2), dead-burned refractory
