Boric acid

Boric-acid-unit-cell-3D-balls

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Borate pH

Borate buffer

Boric acid, also known as hydrogen borate, boracic acid, orthoboric acid and acidum boricum, is a weak, monobasic Lewis acid of boron. However, some of its behaviour towards some chemical reactions suggest it to be tribasic acid in the Brønsted sense as well. Boric acid is often used as an antiseptic, insecticide, flame retardant, neutron absorber, or precursor to other chemical compounds. It has the chemical formula H₃BO₃, and exists in the form of colorless crystals or a white powder that dissolves in water. When occurring naturally, it is called sassolite.

Properties and Chemistry

Boric acid is soluble in boiling water. When added to water, it converts into boric oxide and hydrogen, or in certain reactions, it forms a weak acid, which is why it is considered a weak Lewis acid. The compound has antifungal and antiviral properties, which makes it useful in medical and cosmetic products. Its flame retardant properties are due to its ability to release water, quenching flames in the process.

Applications

Medical

In the medical field, boric acid is used as an antiseptic to treat minor cuts and burns. It is also used in the treatment of yeast infections and athlete's foot, owing to its antifungal properties. Eye wash solutions often contain diluted boric acid for its mild antibacterial effects.

Pest Control

As an insecticide, boric acid acts as a stomach poison for insects such as ants, cockroaches, and termites. It is also used as a preservative in many different applications, including as a wood preservative against rot and insect attack.

Industrial

In industrial applications, boric acid is used in the manufacture of monofilament fiberglass usually referred to as textile fiberglass. It is also a component in the production of glass and ceramics, where it affects the viscosity and surface tension of the molten glass, improving its resistance to heat and chemical attack. Boric acid is used in nuclear power plants as a neutron absorber to control the fission rate of uranium and plutonium.

Safety

While boric acid is generally considered safe for topical application in diluted concentrations, ingestion in large amounts can be toxic to humans and animals. Symptoms of boric acid poisoning include nausea, vomiting, stomach ache, and diarrhea. In severe cases, it can lead to kidney failure, seizures, and even death. Therefore, it is important to handle boric acid with care and keep it out of reach of children and pets.

Environmental Impact

Boric acid can also have an environmental impact. It is toxic to plants in high concentrations, and therefore, its use in outdoor applications should be managed carefully to avoid runoff into water bodies, which can harm aquatic life.