Magnesium oxide
[CAS# 1309-48-4]

Identification

• Classification: API >> Digestive system medication >> Acid and gastric mucosal protective drugs
• Name: Magnesium oxide
• Synonyms: Maglite; Magnesium monoxide
• Molecular Formula: MgO
• Molecular Weight: 40.30
• CAS Registry Number: 1309-48-4
• EC Number: 215-171-9
• SMILES: [O-2].[Mg+2]

Properties

• Density: 3.58 g/mL (Expl.)
• Melting point: 2852 °C (Expl.)
• Boiling point: 3600 °C (Expl.)
• Refraction index: 1.736 (Expl.)
• Water solubility: 6.2 mg/L (20 °C), reacts

Safety Data

• Safety Statements: S24/25

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Skin sensitization	Skin Sens.	1B	H317
Specific target organ toxicity - single exposure	STOT SE	2	H371
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	4	H302
Serious eye damage	Eye Dam.	1	H318
Flammable liquids	Flam. Liq.	2	H225
Aspiration hazard	Asp. Tox.	1	H304
Reproductive toxicity	Repr.	2	H361
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Specific target organ toxicity - repeated exposure	STOT RE	2	H373
Specific target organ toxicity - single exposure	STOT SE	3	H336
Acute toxicity	Acute Tox.	4	H332
Respiratory sensitization	Resp. Sens.	1	H334
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Skin sensitization	Skin Sens.	1	H317

Discovery and Applications

Magnesium oxide (MgO) is a chemical compound that has been utilized for centuries in various applications, spanning from its origins as a refractory material to its more recent uses in environmental and medical fields. It is a white, odorless powder, and its properties make it valuable in both industrial and health-related contexts. The compound was first identified by Joseph Black in the 18th century during his studies of magnesium salts. He discovered that heating magnesia alba, a naturally occurring magnesium carbonate, produced a white, powdery substance, which was later recognized as magnesium oxide. This marked the beginning of its study and use in scientific and industrial fields.

The synthesis of magnesium oxide typically involves the calcination of magnesium carbonate or magnesium hydroxide at high temperatures. When magnesium carbonate (MgCO3) is heated, it decomposes into magnesium oxide and carbon dioxide, a process that is simple and efficient. Another common method for producing magnesium oxide is the thermal decomposition of magnesium hydroxide, where the hydroxide loses water to form the oxide. These methods are well-established and have been used for many years, particularly in the production of magnesium oxide for refractory applications.

Magnesium oxide’s most prominent use is in the steel and cement industries, where it serves as a refractory material. Its high melting point, which exceeds 2,800°C, allows it to withstand extreme temperatures, making it ideal for lining furnaces and kilns. In the steel industry, it helps to stabilize high-temperature environments, preventing the corrosion of equipment and improving the efficiency of the production process. Additionally, magnesium oxide is used in the manufacture of ceramics and glass, contributing to the strength and durability of these materials.

In the medical field, magnesium oxide is commonly used as an antacid to relieve indigestion and heartburn. It neutralizes stomach acid and provides quick relief from the discomfort caused by acid reflux. Magnesium oxide is also a source of magnesium in dietary supplements, which are vital for numerous bodily functions, such as nerve and muscle function, and bone health. Studies have shown that magnesium plays an important role in preventing conditions like osteoporosis and supporting cardiovascular health.

Environmental applications of magnesium oxide have also become increasingly important. It is utilized in wastewater treatment plants to neutralize acidic compounds and help remove contaminants. Moreover, magnesium oxide is involved in carbon capture and storage technology, where it reacts with carbon dioxide to form stable magnesium carbonate, which can reduce the impact of greenhouse gases on the environment.

Despite its many uses, the production of high-purity magnesium oxide requires careful control of temperature and materials to ensure that it meets the specific standards needed for different applications. Research into improving its synthesis and exploring new applications continues, highlighting the ongoing relevance of this compound in modern science and industry.

References

1994. Effect of combined supplementation of magnesium oxide and pyridoxine in calcium-oxalate stone formers. Urological Research, 22(3).
DOI: 10.1007/bf00571844

1998. Ultimate observation of tungsten atoms and clusters adsorbed on single crystalline MgO films. Microscopy Research and Technique, 40(4).
DOI: 10.1002/(sici)1097-0029(19980215)40:4<265::aid-jemt3>3.0.co;2-r

2003. Characterization of oxide layers on amorphous Mg-based alloys by Auger electron spectroscopy with sputter depth profiling. Analytical and Bioanalytical Chemistry, 375(6).
DOI: 10.1007/s00216-003-1787-3