# Is flouride an actual chemical or a misnomer?

I often encounter the term "flouride" used as if it is a chemical. From my understanding, it would be incorrect to call rust oxide and not iron oxide or to call salt chloride instead of sodium chloride. Isn't it incorrect to say drinking water or toothpaste has flouride?

• Fluoride is the anion $\ce{F-}$ of Fluorine which you can easily confirm with Google.
– MaxW
Feb 9 '17 at 6:25
• Yes, I am aware of that. That's not my question. I want to know why is the term fluoride is correct. Feb 9 '17 at 15:30

This Wikipedia article sums it up pretty nicely:

Fluoride [...] is an inorganic, monatomic anion of fluorine with the chemical formula $\ce{F−}$ . Fluoride is the simplest anion of fluorine. Its salts and minerals are important chemical reagents and industrial chemicals, mainly used in the production of hydrogen fluoride for fluorocarbons. 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 only present in trace quantities in water. Fluoride contributes a distinctive bitter taste. It contributes no color to fluoride salts.

Note the term "chemical formula $\ce{F-}$". In toothpaste and drinking water treatment, fluoride is often added as sodium fluoride. So yes it is every bit as much a chemical as, say, chloride in sodium chloride.

You are right in your assertion that fluoride does not exist by itself as a chemical substance. Sodium fluoride ($\ce{NaF}$) and tin(II) fluoride ($\ce{SnF2}$) are the two most common ingredients in fluoride-based toothpaste, and are the source of the fluoride ions. The reason that the cations of the salts are often left off is because fluoride is the active ingredient. Fluoride functions by:

...repair[ing] rather than prevent[ing] damage to the teeth, causing the mineral fluorapatite to be incorporated into damaged tooth enamel.$^{[1]}$

$^{[1]}$Wikipedia, Fluoride Therapy, Mechanism

• Yeah, so the municalities can dump chemical waste in the drinking water and just call it flouride? i.e. Uranium Hexafloiride? Technically, it is a flouride. Why does the US care so much about children's teeth, yet dont care whether they go to bed hungry. I can now see the reasoning behind the flouride conspiracy theories. Feb 9 '17 at 6:57
• @user148298 Bollocks. Utilities can only use approved sources of fluoride (which mimic naturally fluoridated water). Conspiracy theorists on this are about as rational as the Jack D Ripper character in Dr Strangelove (the one who tries to bomb Russia because they have corrupted our precious bodily fluids). Feb 9 '17 at 9:22
• @matt_black "Bollocks?" Please educate yourself and stop being a sock puppet. The US is one of the few countries where water is artificially fluoridated and is rare in Europe. The Cochrane Collaboration found that fluoridation doesn't prevent cavities. Why? Not implying there's a conspiracy, but why add a chemical that is a known toxin. Moreover, why is it not only encouraged, but is a federal mandate in the US? Feb 9 '17 at 15:52
• @user148298 "known toxin" as any decent chemist should know it is the dose that makes the poison. Fluoride is often present in natural water supplies and nothing governments do puts too much fluoride in any water. BTW fluoridation is common in Europe, but often done in milk or salt rather than water. Fluoridation reduces but doesn't stop cavities. And it is present in most toothpaste for exactly that reason. Feb 9 '17 at 17:33