Magnesium carbonate (MgCO3) is a white, powdery substance that is commonly used as an antacid and laxative. It can also be found in some cosmetics and toothpaste. Magnesium carbonate helps to neutralize excess stomach acid and relieve constipation.
| IUPAC name | Magnesium carbonate |
| Molecular formula | MgCO3 |
| CAS number | 546-93-0 |
| Synonyms | Magnesite, Magnesia carbonica, magnesium salt, (MgCO3) |
| InChI | InChI=1S/CH2O3.Mg/c2-1(3)4;/h(H2,2,3,4);/q;+2 |
Magnesium Carbonate Properties
Magnesium Carbonate Formula
The chemical formula for magnesium carbonate is MgCO3. This formula indicates magnesium carbonate contains one Mg+2 ion and one CO3 2- ion. The CO3 2- ion is composed of one C atom and three O atoms. The chemical formula for magnesium carbonate is an important property as it identifies the composition of magnesium carbonate and its constituent elements.
Magnesium Carbonate Molar Mass
The molar mass of MgCO3 is 84.31 g/mol. This value is obtained by adding the atomic masses of magnesium, carbon, and oxygen atoms in one mole of MgCO3. The molar mass is an important physical property of MgCO3 as it is used in various calculations such as determining the number of moles of MgCO3 in a given sample.
Magnesium Carbonate Boiling Point
MgCO3 does not have a definite boiling point as it decomposes before it reaches its boiling point. When heated, MgCO3 decomposes to form magnesium oxide and carbon dioxide. The decomposition of MgCO3 occurs at a temperature of about 350 °C.
Magnesium Carbonate Melting Point
The melting point of MgCO3 is 990 °C. At this temperature, MgCO3 melts and undergoes decomposition to form magnesium oxide and carbon dioxide. The melting point of MgCO3 is an important physical property as it determines the temperature at which MgCO3 can be melted and processed.
Magnesium Carbonate Density g/mL
The density of MgCO3 is 2.958 g/mL. This value is obtained by dividing the mass of one mole of MgCO3 by its volume. The density of MgCO3 is an important physical property as it is used in various applications such as determining the buoyancy of MgCO3 in a given solution.
Magnesium Carbonate Molecular Weight
The molecular weight of MgCO3 is 84.31 g/mol. This value is obtained by adding the atomic masses of magnesium, carbon, and oxygen atoms in one molecule of MgCO3. The molecular weight of MgCO3 is an important physical property as it is used in various calculations such as determining the amount of MgCO3 required for a given chemical reaction.
Magnesium Carbonate Structure
MgCO3 has a trigonal crystal structure. The magnesium ion is located at the center of the structure and is surrounded by six carbonate ions. The carbonate ions are arranged in a hexagonal pattern around the magnesium ion. The crystal structure of MgCO3 is an important property as it determines its physical and chemical properties.
| Appearance | White solid |
| Specific gravity | 2.958 g/mL |
| Color | White |
| Odor | Odorless |
| Molar mass | 84.31 g/mol |
| Density | 2.958 g/mL |
| Melting point | 990 °C |
| Boiling point | Decomposes before reaching boiling point |
| Flash point | Not applicable |
| Water solubility | 0.02 g/L (15 °C) |
| Solubility | Soluble in acids, insoluble in water |
| Vapor pressure | Not applicable |
| Vapor density | Not applicable |
| pKa | 10.3 |
| pH | 9.2-10.2 |
Magnesium Carbonate Safety and Hazards
MgCO3 is considered to be a safe compound. It is not flammable, explosive, or toxic. However, like any other chemical compound, it should be handled with care. Inhaling MgCO3 dust may cause respiratory irritation. When handling MgCO3, wearing appropriate personal protective equipment such as gloves and safety glasses is recommended. MgCO3 should be stored in a cool, dry place away from sources of heat and ignition. Spilled MgCO3 should be cleaned up immediately and disposed of properly. It is important to follow proper safety precautions when handling MgCO3 to prevent any potential hazards.
| Hazard Symbols | None |
| Safety Description | Not classified as hazardous |
| UN IDs | Not applicable |
| HS Code | 2836.60.00 |
| Hazard Class | Not classified as hazardous |
| Packing Group | Not applicable |
| Toxicity | Low toxicity, is not considered to be a significant health hazard when handled properly |
Magnesium Carbonate Synthesis Methods
There are several methods to synthesize MgCO3, including precipitation and thermal decomposition.
To form MgCO3 using the precipitation method, you add a soluble magnesium salt (such as magnesium chloride or magnesium nitrate) to a solution containing a soluble carbonate (such as sodium carbonate or ammonium carbonate). Then, stir the resulting mixture and allow it to stand. This causes the MgCO3 to precipitate out of the solution. After that, filter the precipitate, wash it, and dry it.
To obtain MgCO3 through the thermal decomposition method, one heats magnesium hydroxide or magnesium oxide while introducing carbon dioxide. This reaction leads to the formation of MgCO3 and water vapor. The next step involves collecting, purifying, and drying the MgCO3.
Another method to synthesize MgCO3 is through the reaction of magnesium sulfate and sodium carbonate. Water dissolves the two compounds and then mixes them, causing the precipitation of MgCO3 out of the solution. The process then collects, washes, and dries the precipitate.
Magnesium Carbonate Uses
MgCO3 is a versatile compound with various uses across different industries. Here are some of its uses:
- Dietary supplement: Used as a dietary supplement due to its ability to provide the body with essential magnesium.
- Antacid: Used as an antacid to treat heartburn and indigestion.
- Industrial applications: Used in several industrial applications, such as in the production of ceramics, glass, and cement.
- Cosmetics: Used in cosmetics as a bulking agent, absorbent, and opacifying agent.
- Fireproofing: Used as a fire retardant in several applications, including insulation materials, textiles, and plastics.
- Pharmaceuticals: Used in the production of various pharmaceuticals, such as laxatives and antacids.
- Food and beverage industry: Used as a food additive to regulate the acidity of food products and as an anti-caking agent.
- Sports equipment: Used in sports equipment, such as gymnastics chalk, to improve grip and prevent slipping.
Questions:
Q: Is magnesium carbonate soluble in water?
A: MgCO3 has low solubility in water. At room temperature, only about 0.02 grams of MgCO3 can dissolve in 100 mL of water.
Q: Is MgCO3 soluble?
A: MgCO3 has low solubility in water, meaning it is not highly soluble.
Q: What forms when acetic acid and MgCO3 react?
A: When acetic acid and MgCO3 react, they form magnesium acetate, water, and carbon dioxide. The balanced chemical equation for this reaction is MgCO3 + 2CH3COOH → Mg(CH3COO)2 + H2O + CO2.
Q: The molar solubility of MgCO3 is 1.8 × 10–4 mol/L. What is Ksp for this compound?
A: Ksp value for MgCO3 using the molar solubility:
Ksp = [Mg2+][CO32-], where [Mg2+] is equal to the molar solubility, and [CO32-] is also equal to the molar solubility. Therefore, Ksp = (1.8 × 10–4 mol/L)2 = 3.24 × 10–9.
Q: Which of the following is a product formed when MgCO3 decomposes?
A: When MgCO3 decomposes, it forms magnesium oxide (MgO) and carbon dioxide (CO2).
Q: What is the balanced chemical equation for the reaction used to calculate ΔH°f of MgCO3(s)?
A: The balanced chemical equation for the reaction used to calculate the standard enthalpy of formation (ΔH°f) of MgCO3(s) is: Mg(s) + CO2(g) → MgCO3(s).