Our exposure to fluoride doesn’t just come from fluoridated water. This makes it difficult to determine how much fluoride people are actually consuming. Then there is the added challenge of figuring out how much is actually safe, given how differently people respond to this chemical.
Fluorine is a diatomic gas and the most reactive and electronegative of all the elements. Fluoride is any combination of elements containing the fluorine atom in the -1 oxidation state, per the National Library of Medicine compound summary.