What Are the Main Properties and Applications of Sodium Fluoride?
Sodium fluoride is used for cavity prevention. This makes the teeth healthier and more resistant to acid and bacteria causing decay. Used for the treatment of osteoporosis and otospongiosis in adults, its use is controversial and further studies are expected. Sodium fluoride is a white, crystalline solid or powder. It is best known for its role in the prevention of tooth decay. For this reason, toothpaste or mouthwashes or municipal water sources can be added.
Sodium fluoride formula – NaF
Molecular weight of fluorine = 18.998403 u
Who Discovered Sodium Fluoride
Around the turn of the 20th century, Colorado dentist Dr Frederick S. McKay found that many of his patients had something known as dental fluorosis, which causes staining of their teeth.
How is it Made?
Sodium fluoride, or fluoride chemical formula F − (also written [F] − ), occurs naturally as a villiaumite mineral, but the compound is not commercially produced from that source. Some sodium fluoride is produced as a by-product of the manufacture of phosphate fertilizers. In this process, apatite (a type of calcium phosphate that also contains fluoride and/or chloride) is crushed and treated with sulphuric acid ( H2SO4). The products of this reaction include phosphoric acid (H3PO4), calcium sulfate (CaSO4), hydrogen fluoride (HF), and silicon tetrafluoride (SiF4). Fluoride hydrogen and tetrafluoride silicon can then be converted to sodium fluoride. The compound can also be produced by the treatment of sodium carbonate fluoride hydrogen (Na2CO3) -
2HF + Na2CO3 + 2NaF + H2O + CO2
Physical Properties of Sodium Chloride
The cheapest chemical used for fluoridation is sodium fluorosilicate, also known as sodium silicofluoride. Sodium fluoride solutions are used for the production of hard water-insoluble calcium and magnesium fluoride compounds. It is a dry chemical used in the fluoridation of drinking water, which should be weighed manually and added to the mixing tank.
Part of the resistance to water fluoridation is based on a lack of understanding of the distinction between fluorine, the element, and fluorides, fluorine compounds such as sodium fluoride and potassium fluoride. Fluorides have very different physical, chemical, and biological properties from the fluorine element. For example, fluorine gas is a highly toxic gas that responds violently to most substances, including water. Fluorides, on the other hand, are fairly inert (unreactive) and safe to eat in limited amounts.
Fluorine's molar mass is 18.9984032 g/mol. Fluorine's molar mass effectively rounds to 19 g/mol.
Chemical Properties of Sodium Chloride
Sodium fluoride is an inorganic chemical substance that is a source of fluoride ion in many applications, including dental and radiographic imaging, as it is used as a Fluoride ion F-18.17. Sodium fluoride benefit to dental health was first noticed in the 1930s, as individuals in areas with fluoridated drinking water reported less tooth decay than those without fluoridated water. The use of fluoride in dental practice began in the 1940s. Sodium fluoride can now be found in a variety of dental care gels, varnishes, rinses, toothpaste products, and fluoride treatments.
When was Water Fluoridation Introduced?
In 1945, Grand Rapids, Michigan, changed the water supply fluoride content to 1.0 ppm and thus became the first city to introduce water fluoridation in the world.
Sodium Fluoride Uses
In addition to those related to dental safety, sodium fluoride has a range of commercial and industrial applications. These uses shall include -
As a wood preservation agent
In the production of certain types of pesticides and as an ant and roach control insecticide
In the preparation of other salts of fluoride
In the operation of electroplating
Degassing (removal of gas pockets) during the manufacture of steel
For the manufacture of glass and glass (glass-like) enamels
In ultraviolet and infrared radiation detection devices of the electromagnetic spectrum
For the disinfection of machinery used in breweries and wineries.
Non-Dental Fluoride Sources Include -
Drugs containing perfluorinated compounds
Food and drink made from water that contains fluoride
pesticide use
waterproof and stain-resistant PFC products
Excess Fluoride Exposure May Come From -
public water fluoridation
high concentrations of fluoride in natural freshwater
fluoridated mouth rinse or toothpaste
untested bottled water
inappropriate use of fluoride supplements
some foods
Health Effects of Sodium Fluoride
Sodium Fluoride is toxic and corrosive. If swallowed, it can cause abdominal pain, vomiting, diarrhoea, seizures, collapse, and even lead to death. Inhalation can cause serious irritation to the respiratory tract. Skin or eye contact with solid NaF may cause severe discomfort or burns to the skin and eyes, severe injury, or even death.
FAQs on Sodium Fluoride: Chemistry, Uses & Impact
1. What exactly is Sodium Fluoride and what is its chemical formula?
Sodium Fluoride is an inorganic chemical compound with the formula NaF. It is an ionic salt formed from sodium cations (Na⁺) and fluoride anions (F⁻). In its pure form, it appears as a white or colourless crystalline solid that is readily soluble in water. It is a key source of the fluoride ion, which has significant applications in various fields.
2. How does Sodium Fluoride work to protect teeth from cavities?
Sodium Fluoride protects teeth through a process called remineralisation. Tooth enamel is primarily made of a substance called hydroxyapatite. When you use a product containing NaF, the fluoride ions incorporate into the enamel to form fluorapatite. This new compound is much more resistant to acids produced by oral bacteria, thereby preventing the demineralisation process that leads to tooth decay.
3. Besides toothpaste, what are some other important uses of Sodium Fluoride?
While its dental applications are well-known, Sodium Fluoride has several other important industrial uses. These include:
Water Fluoridation: It is added to public water supplies in controlled amounts to improve community dental health.
Pesticides: It is an active ingredient in some insecticides and rodenticides.
Manufacturing: It is used in the manufacturing of glass, steel, and aluminium as a fluxing agent.
Wood Preservative: It helps protect wood from fungi and insects.
4. What is the difference between Sodium Fluoride and Stannous Fluoride used in dental products?
The primary difference lies in their additional benefits. Both Sodium Fluoride (NaF) and Stannous Fluoride (SnF₂) are effective at preventing cavities by supplying fluoride ions. However, Stannous Fluoride offers extra advantages; it has significant antibacterial properties that help reduce plaque biofilm and control gingivitis. Sodium Fluoride's main function is solely focused on strengthening tooth enamel.
5. Why is Sodium Fluoride classified as a salt in chemistry?
Sodium Fluoride is classified as a salt because it is the product of a neutralisation reaction between an acid and a base. Specifically, it is formed from the reaction of a strong base, Sodium Hydroxide (NaOH), and a weak acid, Hydrofluoric Acid (HF). When dissolved in water, it completely dissociates into its constituent ions (Na⁺ and F⁻), which is a defining characteristic of an ionic salt.
6. Are there any health risks associated with the use of Sodium Fluoride?
When used as directed in recommended concentrations (e.g., in toothpaste or fluoridated water), Sodium Fluoride is safe and effective. However, excessive, long-term ingestion can lead to health issues. The most common risk is dental fluorosis, which causes cosmetic white spots or streaks on the teeth. In very high and chronic doses, it can lead to a more severe condition called skeletal fluorosis, which affects bones and joints.
7. What are the potential environmental impacts of Sodium Fluoride?
While beneficial in controlled applications, the release of high concentrations of fluoride into the environment from industrial sources can be a concern. Fluoride ions can accumulate in soil and water. This accumulation can be toxic to some plants, leading to decreased growth and crop yield. It can also be harmful to aquatic ecosystems if concentrations become too high, affecting the health of fish and other organisms.
8. How is Sodium Fluoride produced on an industrial scale?
Industrially, Sodium Fluoride is typically synthesised by neutralising hydrofluoric acid (HF). The neutralisation is carried out using a sodium-containing base, most commonly sodium hydroxide (NaOH) or sodium carbonate (Na₂CO₃). The resulting reaction produces the salt, Sodium Fluoride, which is then purified for its various applications.
