An ionic form of fluorine.
Fluoride is a compound which occurs naturally in both groundwater and surface water. It includes any compound that contains either the F-ion or fluorine with an oxidation state of -1. It is commonly found in nature e.g. as the mineral fluorspar (calcium fluorite Ca F2).
Why is fluoride important?
In drinking water flouride decreases the incidence of tooth decay when the water is consumed during the period of enamel calcification. Excessive quantities in drinking water consumed by children during the period of enamel calcification may cause a characteristic discoloration of the teeth.
Drinking water guidelines for flouride