Sodium fluoride

Sodium fluoride is an ionic compound with the formula NaF. This colourless solid is the main source of the fluoride ion in diverse applications. NaF is less expensive and less hygroscopic than KF, but otherwise the potassium salt is more widely used.

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Chemical structure and properties

NaF crystallizes in the sodium chloride motif where both Na⁺ and F⁻ occupy octahedral coordination sites.^[1]

It is usually used as a reagent for the synthesis of fluorides. Representative substrates include electrophilic chlorides including acyl chlorides, sulfur chlorides, and phosphorus chloride.^[2] Like other fluorides, NaF finds use in desilylation in organic synthesis.

Uses

Fluoride salts are used widely to enhance the strength of teeth by the formation of fluoroapatite, a naturally occurring component of tooth enamel. In the US, NaF was once used to fluoridate drinking water but its use has been displaced by hexafluorosilicic acid (H₂SiF₆) or its sodium salt (Na₂SiF₆). Toothpaste often contains sodium fluoride to prevent cavities.

Sodium fluoride was also used as an antibiotic, as rat poison, and in ceramics.

See also

• Fluorine
• Water fluoridation
• Fluoride poisoning
• Caries
• Osteoporosis
• Insecticide
• Cryolite
• Light metals

References

1. ^ Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.
2. ^ Halpern, D. F. “Sodium Fluoride” Encyclopedia of Reagents for Organic Synthesis, 2001, John Wiley & Sons. DOI: 10.1002/047084289X.rs071.