Fluorine

Beryllium fluoride

A glassy, covalent compound whose network structure closely resembles silica, unusual behavior for what looks like a simple metal fluoride.

Used for: Component of molten-salt nuclear reactor fuel (FLiBe)

Calcium fluoride

An ionic salt found naturally as the mineral fluorite, which crystallizes in cubes and often fluoresces under ultraviolet light.

Used for: Source of fluorine and hydrofluoric acid, optical lenses, steel flux

Cesium fluoride

A very water-soluble ionic salt that serves as a source of "naked" fluoride ion in organic synthesis, thanks to cesium's weak attraction to it.

Used for: Fluoride source and mild base in organic synthesis

Hydrofluoric acid

A weak acid in water despite fluorine's high reactivity, yet uniquely able to dissolve glass by breaking apart silicon-oxygen bonds.

Used for: Glass etching, semiconductor manufacturing, metal cleaning

Iridium hexafluoride

A volatile, deep yellow solid and one of the most powerful oxidizing agents among the transition-metal fluorides, decomposing readily and attacking glassware.

Used for: Research reagent for fluorination chemistry

Krypton difluoride

A rare, thermally unstable compound of a noble gas, made by exposing krypton and fluorine to electrical discharge or radiation at very low temperatures; it decomposes back to its elements near room temperature.

Used for: Laboratory demonstration of noble-gas reactivity and a powerful fluorinating agent

Lanthanum fluoride

An insoluble crystalline solid whose ion-conducting properties make it the active membrane material in fluoride-selective electrodes.

Used for: Membrane material in fluoride ion-selective electrodes

Lithium fluoride

An ionic salt of small, tightly bound ions that gives it an unusually wide window of optical transparency stretching into the ultraviolet.

Used for: UV and infrared optical windows and lenses, reactor coolant salts

Neodymium fluoride

A pale violet, insoluble crystalline solid used as a component in specialty optical coatings and laser glass formulations.

Used for: Component in optical coatings and neodymium-doped laser glass

Neptunium hexafluoride

A volatile, reddish-brown crystalline solid, structurally analogous to uranium and plutonium hexafluoride, that sublimes at moderate temperatures. Its volatility has made it a useful probe compound in laboratory studies of actinide separation chemistry.

Plutonium hexafluoride

A volatile, brown-red solid that, like uranium hexafluoride, sublimes readily into a reactive gas. It is markedly less stable than UF6, and decomposes back to the tetrafluoride under only mild heating.

Praseodymium fluoride

A green, insoluble crystalline solid used as a doping additive to modify the color and properties of specialty optical glass and ceramics.

Used for: Additive in specialty optical glass and ceramic formulations

Radon difluoride

A compound inferred from radiotracer experiments in which radon gas reacts with fluorine to form a nonvolatile solid; because radon decays so quickly, it has never been produced or observed in a visible, weighable amount, so its properties remain only partly established.

Used for: No practical use — studied only to probe the chemistry of a normally 'inert' gas

Sodium fluoride

A simple ionic salt that dissolves to release fluoride ions, which help strengthen tooth enamel against acid attack.

Used for: Water fluoridation, toothpaste additive, pesticide

Sulfur hexafluoride

A colorless, odorless gas with an octahedral shape that is chemically inert and an excellent electrical insulator.

Used for: Insulating gas in high-voltage electrical equipment

Thorium tetrafluoride

A white, high-melting solid that serves as the key intermediate between thorium ore concentrates and metallic thorium, produced by reducing it with calcium metal.

Used for: Intermediate in the production of thorium metal

Tin(II) fluoride

A water-soluble tin salt, commonly called stannous fluoride, that delivers fluoride ions to strengthen tooth enamel against decay.

Used for: Active ingredient in fluoride toothpaste

Tungsten hexafluoride

A dense, corrosive gas, notable for being among the heaviest gases known under ordinary conditions, used as the fluorine and tungsten source in vapor deposition processes.

Used for: Precursor gas for depositing tungsten metal films in semiconductor chip wiring

Uranium hexafluoride

A volatile, colorless solid that sublimes readily and turns into a dense, corrosive gas just above room temperature. Its six fluorine atoms make it the only uranium compound volatile enough to be processed by gas centrifuge or diffusion.

Used for: Feedstock gas for uranium enrichment

Uranium tetrafluoride

A green, non-volatile crystalline solid nicknamed "green salt," made by reacting uranium oxide with hydrofluoric acid. It's the intermediate step between uranium oxide and the volatile hexafluoride used for enrichment.

Used for: Intermediate in uranium enrichment and uranium metal production

Xenon difluoride

A colorless crystalline solid and the simplest stable noble-gas compound, proof that xenon can form real chemical bonds despite its inert reputation.

Used for: Selective fluorinating and etching agent in semiconductor microfabrication

Xenon hexafluoride

The most reactive of the three well-characterized xenon fluorides, a colorless solid that reacts readily with trace moisture and even attacks glass.

Used for: Strong fluorinating agent in specialized inorganic synthesis

Xenon tetrafluoride

A colorless, square-planar crystalline solid and one of the first noble-gas compounds ever synthesized, formed by heating xenon and fluorine gas together under pressure.

Used for: Research reagent and strong fluorinating agent

Yttrium fluoride

A white, water-insoluble solid used as an optical coating material for its low refractive index and broad transparency range.

Used for: Anti-reflective optical coatings for lenses from the UV to the IR