Fluoride and its Occurrence
- Fluorides include compounds that contain ionic fluoride and those in which fluoride does not dissociate.
- Sulfur hexafluoride and carbon tetrafluoride are not sources of fluoride ions under ordinary conditions.
- Fluorine is estimated to be the 13th-most abundant element in Earth's crust.
- It is widely dispersed in nature, entirely in the form of fluorides.
- The most commercially important fluoride mineral is fluorite.
- Natural weathering of rocks and human activities release fluorides into the biosphere.
- Some parts of Asia have dangerously high levels of fluoride in groundwater.
- Fluoride is naturally present in groundwater, fresh and saltwater sources, and rainwater.
- Seawater fluoride levels range from 0.86 to 1.4 mg/L, with an average of 1.1 mg/L.
- Freshwater concentrations range from 0.01 to 0.3 mg/L in surface water.
- Groundwater concentrations vary depending on local fluoride-containing minerals.
- All vegetation contains some fluoride absorbed from soil and water.
- Tea leaves contain higher levels of fluoride compared to other plants.
- Mature tea leaves can contain 10 to 20 times the fluoride levels of young leaves.
- Fluoride concentration in plants varies depending on the environment.
- Some plants concentrate fluoride more than others.
Chemical Properties and Applications of Fluoride
- Fluoride can act as a base and combine with a proton to form hydrogen fluoride.
- In aqueous solution, fluoride is a weak base with a p value of 10.8.
- Soluble fluoride salts can decompose to hydroxides or oxides upon contact with moisture.
- Salts containing fluoride have different structures, with four or six cations surrounding the fluoride anion.
- Inorganic fluorides in water contain fluoride ions and bifluoride ions.
- Fluoride salts and hydrofluoric acid are valuable fluorides in industrial applications.
- Organofluorine compounds are widely used in drugs, polymers, refrigerants, and inorganic compounds.
- Fluoride is used in the production of cryolite for aluminum smelting.
- Fluorite is used to separate slag in steel-making.
- Uranium hexafluoride is used in the purification of uranium isotopes.
- Fluoride-containing compounds are used in topical and systemic fluoride therapy for preventing tooth decay.
- Sodium fluoride and sodium monofluorophosphate are commonly used in fluoride therapy.
- Water fluoridation is considered one of the 10 great public health achievements of the 20th century.
- Fluoridated toothpaste is widely used for cavity prevention.
- Fluoride salts are commonly used as inhibitors of phosphatases in biological assays.
- Fluoride mimics the nucleophilic hydroxide ion in the active sites of phosphatase enzymes.
- Beryllium fluoride and aluminum fluoride are also used as phosphatase inhibitors.
- Laboratory reagents containing fluoride are important in studying phosphatase activity.
Fluoride in Biochemistry and Human Health
- Fluoride and hydrogen fluoride are considered equivalent in biochemistry.
- Fluoride is a micronutrient necessary for preventing dental cavities and promoting healthy bone growth.
- Tea is a known accumulator of fluorine compounds, which can release fluoride ions when brewed.
- Approximately 50% of absorbed fluoride is excreted renally within 24 hours.
- Fasting can increase the rate of fluoride absorption to near 100%.
Dietary Recommendations and Safety of Fluoride
- The U.S. Institute of Medicine (IOM) sets dietary recommendations for fluoride intake.
- Adequate Intake (AI) for women is 3.0mg/day and for men is 4.0mg/day.
- The major risk of fluoride deficiency is an increased risk of tooth cavities.
- The IOM sets a tolerable upper intake level (UL) of 10mg/day for fluoride.
- The European Food Safety Authority (EFSA) sets an adult UL at 7.0mg/day.
- The highest safe daily intake of fluoride is 10mg/day for most people.
- Young children have smaller safe intake values, ranging from 0.7mg/d to 2.2mg/d for infants.
- Soluble fluoride salts, such as sodium fluoride, are toxic and can cause accidental or self-inflicted deaths from acute poisoning.
- Treatment for fluoride poisoning may involve administration of calcium hydroxide or calcium chloride to prevent further absorption and injection of calcium gluconate to increase calcium levels in the blood.
Fluoride Sources and Health Implications
- Tea, including brick tea, contains aluminum and fluoride.
- Fluoride can be found in dental products such as toothpaste.
- Certain chemicals, like anhydrous phosphazenium fluorides, can be sources of extremely reactive fluoride ions.
- Cobaltocenium fluoride is a novel source of naked fluoride.
- Imidazolium fluoride can be used as a free fluoride reagent.
- Fluoride concentration in tea and herbal infusions can contribute to daily fluoride intake.
- Black tea has been reviewed for its potential health benefits or harm.
- Fluoride in drinking water has been a subject of debate and research.
- Fluoride has been found to be effective in preventing dental caries in adults.
- Community water fluoridation has been recognized as a public health achievement.
- Fluoride toothpastes are used for preventing dental caries.
- Dentifrices with different fluoride concentrations can remineralize initial carious lesions.
- High-risk strategies, including fluoride application, are used to control dental caries.
- The World Health Organization provides guidelines on fluoride intake from drinking water.
- The European Food Safety Authority has established dietary reference values for fluoride.
- The United States Department of Agriculture provides nutrient lists including fluoride content.
- Tolerable upper intake levels for fluoride have been established.
- Clinical toxic
Fluoride (/ˈflʊəraɪd, ˈflɔːr-/) is an inorganic, monatomic anion of fluorine, with the chemical formula F−
(also written [F]−
), whose salts are typically white or colorless. Fluoride salts typically have distinctive bitter tastes, and are odorless. Its salts and minerals are important chemical reagents and industrial chemicals, mainly used in the production of hydrogen fluoride for fluorocarbons. Fluoride is classified as a weak base since it only partially associates in solution, but concentrated fluoride is corrosive and can attack the skin.
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| Names | |||
|---|---|---|---|
| IUPAC name
Fluoride
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| Identifiers | |||
3D model (JSmol)
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| ChEBI | |||
| ChEMBL | |||
| ChemSpider | |||
| 14905 | |||
| KEGG | |||
| MeSH | Fluoride | ||
PubChem CID
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| UNII | |||
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| Properties | |||
| F− | |||
| Molar mass | 18.998403163 g·mol−1 | ||
| Conjugate acid | Hydrogen fluoride | ||
| Thermochemistry | |||
Std molar
entropy (S⦵298) |
145.58 J/mol K (gaseous) | ||
Std enthalpy of
formation (ΔfH⦵298) |
−333 kJ mol−1 | ||
| Related compounds | |||
Other anions
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Fluoride is the simplest fluorine anion. In terms of charge and size, the fluoride ion resembles the hydroxide ion. Fluoride ions occur on Earth in several minerals, particularly fluorite, but are present only in trace quantities in bodies of water in nature.
