50 Fun Facts About Fluorine

Which wall-climbing lizards cannot stick to Teflon, the fluorine-based plastic that defeats their grip?

Geckos grip walls using weak van der Waals forces, and Teflon's tightly held fluorine atoms resist those forces so well that a gecko's feet simply slide off.

In which TV drama does hydrofluoric acid, a fluorine compound, dissolve a body and then a bathtub?

Breaking Bad's second episode has Jesse skip the plastic bin Walt asked for, so the acid dissolves the tub as well and the ceiling below it collapses.

Hydrofluoric acid, a fluorine compound classed as a weak acid, famously dissolves which material?

Glass is mostly silica, which the acid converts into fluorine compounds that drift or wash away, so the acid has to be bottled in plastic instead.

Which sea predators have teeth of fluorapatite, the fluorine mineral that fluoride builds on human teeth?

Sharks build the outer layer of every tooth from fluorapatite, a mineral that resists acid attack far better than the one in untreated human teeth.

The French chemist who first isolated fluorine also used an electric furnace to try making which gems?

Diamonds were his target in the electric arc furnace he helped develop, and he also found a new mineral in fragments of an Arizona meteorite.

Which James Cameron film shows a real rat breathing while submerged in a fluorine-based liquid?

The Abyss filmed the scene for real, and the same technique has been proposed for deep divers and for patients with badly damaged lungs.

Which popular drink's plant soaks up fluorine compounds from soil and releases fluoride when brewed?

Tea leaves build up fluoride as they age, so mature leaves hold 10 to 20 times as much as young leaves from the same plant.

The Manhattan Project used tons of fluorine to turn which metal into a gas for enriching bomb fuel?

Uranium bonded to fluorine becomes a gas whose lighter, bomb-grade molecules can be sifted out, and large-scale fluorine production began for that job.

Which waterproof, breathable fabric is made by stretching Teflon, a fluorine-based plastic?

Gore-Tex was born in 1969 when Bob Gore gave a heated rod of the plastic a sudden yank and it stretched about 800% instead of snapping.

Fluorine-containing CFC gases from aerosol cans were banned for thinning which part of the atmosphere?

Ozone layer damage showed up in the 1980s as a dramatic seasonal hole over Antarctica, which is slowly recovering now that the gases are phased out.

Which Procter & Gamble brand launched in 1955 as the first clinically proven fluoride toothpaste?

Crest grew out of a research project at Indiana University, and in 1960 the American Dental Association reported that it really did help prevent decay.

Fluoride, an ion of fluorine, strengthens which outer layer of teeth, the body's hardest substance?

Enamel that takes up fluoride rebuilds itself partly as fluorapatite, which stands up to the acids made by mouth bacteria better than the original mineral.

Fluorine, bromine and iodine belong to which family of elements, whose name means salt former?

Halogens react with metals to make salts, ordinary table salt among them, and fluorine is the lightest member of the family.

Which blockbuster antidepressant, known generically as fluoxetine, has three fluorine atoms per molecule?

Prozac was one of the first antidepressants to act selectively on serotonin, sparing patients many of the side effects of older drugs.

Which family of fluorine compounds, used in stain-resistant coatings, is nicknamed forever chemicals?

PFAS earned the nickname because their fluorine bonds are so stable that the compounds linger in the environment for a very long time.

Hydrofluoric acid, a fluorine compound, can kill by seeping through skin and binding which blood mineral?

Calcium stripped from the blood can stop the heart, which is why these burns are treated straight away with calcium gluconate gel.

Fluorite, the main ore of fluorine, defines the value 4 on which scale used by geologists?

Mohs scale ranks minerals by which can scratch which, so fluorite scratches calcite at 3 but is itself scratched by apatite at 5.

Fluorite, the mineral that gave fluorine its name, often glows when lit by which invisible light?

Ultraviolet light makes many fluorite crystals shine, and in 1852 George Stokes named the whole effect fluorescence after the mineral.

Which gemstone, the traditional November birthstone, has fluorine built into its crystal structure?

Topaz is a silicate of aluminum and fluorine, and it is the state gem of Utah, where rockhounds dig crystals at Topaz Mountain.

Which French chemist isolated fluorine in 1886 and won a Nobel Prize for it twenty years later?

Henri Moissan succeeded by passing electricity through a chilled fluorine solution, and he died just two months after collecting the prize.

Fluorine scores 3.98, the highest of any element, on the Pauling scale of which chemical property?

Electronegativity measures how strongly an atom pulls shared electrons towards itself, and fluorine's unmatched pull is why it reacts with almost everything.

Which faint color is pure fluorine gas, a shade that brightens when it condenses to liquid at −188 °C?

Pale yellow fluorine has a biting smell that the nose can pick up at just 20 parts per billion, a useful warning given how toxic the gas is.

Which noble gas has never been seen to form a compound with fluorine, which reacts with almost every other element?

Neon has never yielded a fluoride, whereas radon reacts readily, krypton needs special conditions and even argon forms one fluorine compound in extreme cold.

Chemist Neil Bartlett used a fluorine compound to prove noble gases can react, starting with which gas?

Xenon had defied every attempt at a reaction until Bartlett's 1962 experiment, a result that surprised many chemists.

Which heavy fluorine gas, used to insulate electrical switchgear, makes a voice sound much deeper when inhaled?

Sulfur hexafluoride is so much denser than air that it deepens the voice, the reverse of helium, and it is also the most potent greenhouse gas known.

Which 1987 treaty, the first ratified by every United Nations member, phased out fluorine-containing CFC gases?

The Montreal Protocol has been ratified by 198 parties, and former UN chief Kofi Annan called it perhaps the single most successful international agreement.

Which English inventor of the miners' safety lamp damaged his eyes experimenting with fluorine compounds?

Humphry Davy got off lightly: the same fumes later killed two other chemists, and the injured researchers became known as the fluorine martyrs.

Which country is the biggest user of 1080, a fluorine-based poison air-dropped to kill invasive possums?

New Zealand has no native ground-based mammals to harm, and the same poison occurs naturally in at least 40 plant species as a defense against grazers.

Which 3M fabric protector was discovered when a fluorine-based liquid spilled on a lab worker's tennis shoe?

Scotchgard began in 1953 when the splash on Joan Mullan's shoe refused to wash off, and chemists Patsy Sherman and Samuel Smith turned it into a product.

Which DuPont chemist discovered Teflon by accident when a cylinder of fluorine-based gas turned to white powder?

Roy Plunkett was trying to make a new refrigerant in 1938 when the gas seemed to vanish, so he cut the cylinder open and found a waxy solid inside.

Which American engineer helped invent both leaded gasoline and Freon, the fluorine-based refrigerant gas?

Thomas Midgley was showered with medals in his lifetime, but both inventions were later banned for the harm they did to human health and the environment.

Freon, the first fluorine-based refrigerant, came from the Frigidaire division of which American carmaker?

General Motors teamed up with DuPont in 1930 to sell the gas, which replaced more toxic coolants and boosted demand for kitchen fridges.

The chemist who isolated fluorine won the 1906 Nobel Prize by a single vote over which Russian rival?

Dmitri Mendeleev, who drew up the periodic table, lost by that one vote and died the following year without ever receiving a Nobel.

The apparatus that first isolated fluorine used corrosion-resistant electrodes of iridium alloyed with which metal?

Platinum on its own corroded too quickly, so it was alloyed with iridium for resistance and the whole cell was chilled to slow fluorine's attack.

The name fluorine comes from which meaning of a Latin verb, chosen because fluorite helps ores melt?

To flow is the sense of the Latin fluere, because smelters added the mineral to make molten ore and slag run more easily.

Which Michigan city, long famous for furniture, was first in the United States to add fluoride to tap water?

Grand Rapids began the experiment in January 1945, and results published in 1950 showed a significant drop in cavities.

Dentist Frederick McKay traced fluoride's benefits by studying mysterious brown-stained teeth in which US state?

Colorado brown stain, as locals in Colorado Springs called it, came with a surprise: the mottled teeth were unusually free of cavities.

Which rare fluorine mineral, mined for decades at a single site in Greenland, is used to smelt aluminum?

Cryolite, whose name is Greek for frost stone, dissolves aluminum ore so the metal can be pulled out by electricity; the Greenland mine closed in 1987.

Radioactive fluorine-18, which loses half its strength in under two hours, is a key tracer for which hospital scan?

PET stands for positron emission tomography: the isotope gives off positrons, usually after it has been attached to a sugar that hungry tumors soak up.

Which fluorine compound, code-named N-Stoff by Nazi Germany, is reactive enough to set sand and asbestos alight?

Chlorine trifluoride was planned as an incendiary weapon but never used in war, and a spill of it once burned through 30 cm of concrete.

The strongest superacid known pairs hydrogen fluoride with a fluorine compound of which element?

Antimony pentafluoride and hydrogen fluoride together make fluoroantimonic acid, which is stronger than pure sulfuric acid by many orders of magnitude.

Which German father of mineralogy first described fluorite, the chief ore of fluorine, as a smelting aid?

Georgius Agricola coined Latin names for hundreds of mining terms, and his word for these useful stones eventually gave fluorine its name.

Fl, a symbol used for fluorine in early papers, now belongs to which superheavy element, number 114?

Flerovium took the symbol in 2012 in honor of a Russian laboratory, long after fluorine had settled on a plain F.

Blue John, a rare banded variety of the fluorine mineral fluorite, is mined at Castleton in which English county?

Derbyshire Blue John has become so scarce that only a few hundred kilograms are mined each year, all of it for ornaments and jewelry.

Which fluorine-containing cholesterol drug earned more revenue than any other medicine before going generic in 2011?

Lipitor is one of many medicines given a fluorine atom to slow their breakdown in the body, a trick used in about a fifth of modern drugs.

Sevoflurane, desflurane and halothane, all rich in fluorine, belong to which class of hospital drugs?

Anesthetics breathed in as vapor are mostly fluorine-rich, and the newer ones barely dissolve in blood, so patients wake up faster.

One theory holds that much of the universe's scarce fluorine is forged by neutrinos during which cosmic events?

Supernovae are one of three proposed sources, a puzzle that exists because ordinary stellar fusion skips fluorine and leaves it far rarer than its neighbors.

The fluorine compound most often added to American tap water is a by-product of making which farm product?

Fertilizer plants produce it while processing phosphate rock, which makes it an inexpensive liquid for water utilities to buy.

Which French pioneer of electromagnetism first proposed that hydrofluoric acid hid a new element, fluorine?

André-Marie Ampère, whose name lives on in the unit of electric current, made the suggestion in 1810, decades before anyone managed to isolate the element.

Before Teflon, the fluorine plastic, reached frying pans, French engineer Marc Grégoire used it to coat which gear?

Fishing tackle was his test bed until his wife Colette urged him in 1954 to try her cooking pans, which launched the Tefal brand.