Fluorine as an element was first successfully isolated in 1886 by the French chemist Henri Moissan, using electrolysis of a potassium hydrogen fluoride and hydrogen fluoride mixture.

Early observations

Long before isolation of elemental fluorine, chemists already knew fluorine- containing minerals.

In 1529, Georgius Agricola described the mineral fluorite (fluorspar), used to help metal ores melt more easily during smelting.

Path to discovery

Throughout the 18th and 19th centuries, many chemists tried to obtain fluorine from hydrofluoric acid and fluorides, but its extreme reactivity made these attempts dangerous and often fatal.

These hazardous experiments eventually led to Henri Moissan’s successful isolation of fluorine gas by electrolysis in 1886, a breakthrough that later earned him the Nobel Prize in Chemistry.

TL;DR: Fluorine‑containing minerals were described in the 1500s, but elemental fluorine itself was finally discovered and isolated in 1886 by Henri Moissan.