fluoride (n.)

non-metallic element, 1813, coined by English chemist Sir Humphry Davy from fluorspar ("calcium fluoride," modern fluorite), the late 18c. name of the mineral where it was first found (see fluor) + chemical suffix -ine (2). Not isolated until 1886. Related: Fluorinate; fluorination.

word-forming element used in chemistry to coin names for simple compounds of one element with another element or radical; originally abstracted from oxide, which was the first so classified, in which the -ide is from acide "acid."

The suffix is really -dus (-do-), the -i- repr. the orig. or supplied stem-vowel ; it occurs without the vowel in absurdus, absurd, blandus, bland, crudus, raw (crude), etc. [Century Dictionary]