Magnesium bisulfite (Mg(HSO3)2) is a chemical compound made up of magnesium, sulfur, and oxygen. It is commonly used in the food industry as a preservative and antioxidant to prevent spoilage and discoloration.
| IUPAC Name | Magnesium hydrogen sulfite |
| Molecular Formula | Mg(HSO3)2 |
| CAS Number | 13774-25-9 |
| Synonyms | Magnesium bisulphite; Magnesium hydrogen sulfite; Bisulfite of magnesia |
| InChI | InChI=1S/2H2O3S.Mg/c21-4(2)3;/h2(H2,1,2,3);/q;;+2/p-2 |
Magnesium Bisulfite Properties
Magnesium Bisulfite Formula
The chemical formula of magnesium bisulfite is Mg(HSO3)2. The formula represents the number of atoms of each element present in one molecule of the compound. The formula of magnesium bisulfite is essential in determining the chemical reactions that the compound can undergo.
Magnesium Bisulfite Molar Mass
Mg(HSO3)2 has a molar mass of 186.45 g/mol. This value represents the weight of one mole of the compound in grams. The molar mass of a compound is essential in determining the amount of a substance required to perform chemical reactions. The molar mass of Mg(HSO3)2 is calculated by adding the atomic weights of each element in the compound. Magnesium has an atomic weight of 24.305 g/mol, sulfur has an atomic weight of 32.06 g/mol, and oxygen has an atomic weight of 15.999 g/mol.
Magnesium Bisulfite Boiling Point
Mg(HSO3)2 has no boiling point as it decomposes upon heating. However, it can release sulfur dioxide gas and sulfur trioxide gas when heated in the presence of an acid. These gases can irritate the respiratory system and cause severe health effects when inhaled. It is, therefore, essential to handle Mg(HSO3)2 with care and follow safety precautions when using it in industrial processes.
Magnesium Bisulfite Melting Point
Mg(HSO3)2 has a melting point of 110 °C. This value represents the temperature at which the compound changes from a solid state to a liquid state. Mg(HSO3)2 has a low melting point, making it easy to melt and use in various industrial processes. However, it can decompose at high temperatures, leading to the release of harmful gases.
Magnesium Bisulfite Density g/mL
Mg(HSO3)2 has a density of 2.35 g/mL. This value represents the amount of mass in grams present in one milliliter of the compound. The density of Mg(HSO3)2 is higher than that of water, which has a density of 1 g/mL. The high density of Mg(HSO3)2 makes it useful in various applications, including as a preservative and antioxidant in the food industry.
Magnesium Bisulfite Molecular Weight
Mg(HSO3)2 has a molecular weight of 186.45 g/mol. This value represents the sum of the atomic weights of all atoms in the compound. The molecular weight of Mg(HSO3)2 is essential in determining the amount of the compound required to perform chemical reactions.
Magnesium Bisulfite Structure
Mg(HSO3)2 has a crystalline structure and belongs to the orthorhombic crystal system. The compound consists of magnesium cations (Mg2+) and bisulfite anions (HSO3-). The bisulfite anions are tetrahedral in shape, while the magnesium cations are octahedral in shape. The crystal structure of Mg(HSO3)2 makes it stable and allows it to be used in various applications, including as a food preservative.
Magnesium Bisulfite Solubility
Mg(HSO3)2 is highly soluble in water, with a solubility of approximately 64 g/100 mL at 20°C. It is also soluble in methanol, but insoluble in most organic solvents. The solubility of Mg(HSO3)2 may vary depending on factors such as temperature and pH.
| Appearance | White powder |
| Specific Gravity | 2.35 g/cm3 |
| Color | White |
| Odor | Odorless |
| Molar Mass | 186.45 g/mol |
| Density | 2.35 g/mL |
| Melting Point | 110 °C |
| Boiling Point | Decomposes |
| Flash Point | Not applicable |
| Water Solubility | Soluble |
| Solubility | Soluble in water and ethanol |
| Vapour Pressure | Not applicable |
| Vapour Density | Not applicable |
| pKa | 1.91 |
| pH | 4.5 – 5.5 |
Magnesium Bisulfite Safety and Hazards
Mg(HSO3)2 can pose several health and safety hazards if not handled with care. It can release sulfur dioxide and sulfur trioxide gases when heated or exposed to acidic conditions. These gases can cause respiratory irritation, coughing, and shortness of breath if inhaled. Mg(HSO3)2 can also cause skin irritation and redness upon contact. It is essential to wear protective clothing and equipment, such as gloves and goggles, when handling Mg(HSO3)2. Additionally, it should be stored in a cool, dry place away from heat sources and incompatible materials. Proper handling and storage procedures can minimize the risk of hazards associated with Mg(HSO3)2.
| Hazard Symbols | Xi: Irritant |
| Safety Description | Avoid contact with skin and eyes. Wear protective clothing and equipment. Keep away from heat and incompatible materials. |
| UN IDs | UN 2693 |
| HS Code | 2831.10.00 |
| Hazard Class | 8 – Corrosive substances |
| Packing Group | III |
| Toxicity | May cause skin and eye irritation. Harmful if inhaled or ingested. May cause respiratory irritation and coughing. |
Magnesium Bisulfite Synthesis Methods
One can synthesize Mg(HSO3)2 through various methods, including:
- Reaction of Magnesium Hydroxide with Sulfur Dioxide: In the reaction of magnesium hydroxide with sulfur dioxide, the two substances react to produce Mg(HSO3)2 and water.
- Direct Reaction of Magnesium Oxide with Sulfur Dioxide: At high temperatures, sulfur dioxide gas reacts directly with magnesium oxide to yield Mg(HSO3)2 and oxygen.
- Reaction of Magnesium Sulfate with Sulfur Dioxide: In the presence of a reducing agent, magnesium sulfate reacts with sulfur dioxide gas, resulting in the production of Mg(HSO3)2.
- Magnesium Carbonate with Sulfur Dioxide: The reaction between magnesium carbonate and sulfur dioxide gas produces Mg(HSO3)2 and carbon dioxide.
- Reaction of Magnesium Oxide with Sulfuric Acid and Sulfur Dioxide: When reacting magnesium oxide with sulfuric acid and sulfur dioxide gas, the reaction produces Mg(HSO3)2 and water.
Magnesium Bisulfite Uses
Mg(HSO3)2 has a variety of uses in different industries. Here are some common applications:
- Food and Beverage Industry: Used as a preservative in the food and beverage industry to prevent oxidation and microbial growth. It is commonly used in fruit juices, wine, and beer.
- Water Treatment: Used in water treatment as a reducing agent to remove chlorine and other oxidizing agents. It is effective in controlling odor and taste in water.
- Textile Industry: Used as a bleaching agent in the textile industry. It is effective in removing stains and improving the color of fabrics.
- Pharmaceutical Industry: Used as a reducing agent in the pharmaceutical industry. It is used to convert nitro groups to amino groups in various drug molecules.
- Pulp and Paper Industry: Used in the pulp and paper industry as a bleaching agent. It is effective in removing lignin from wood pulp and improving the brightness of paper.
- Agriculture: Used in agriculture as a soil amendment to correct magnesium deficiencies in the soil. It is also used as a foliar fertilizer to improve plant growth and yield.
Questions:
Q: What are the thermodynamic properties of magnesium bisulfite?
A: The thermodynamic properties of Mg(HSO3)2 include its boiling point of 250 °C, melting point of 70-72 °C, and density of 1.84 g/mL.
Q: What is the chemical formula of magnesium bisulfite?
A: The chemical formula of magnesium bisulfite is Mg(HSO3)2.
Q: Where can I buy magnesium bisulfite?
A: Mg(HSO3)2 can be purchased from various chemical suppliers and distributors. It is commonly available in both bulk and small quantities. Some online platforms such as Sigma Aldrich, Fisher Scientific, and VWR International also offer Mg(HSO3)2 for purchase. It is important to ensure that the supplier is reputable and that the product meets the required standards for your intended application.