chemistry

Origin and occurrence of fluorine

Origin and occurrence of fluorine is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Origin and occurrence of fluorine rather than just read about it. In short: Fluorine is relatively rare in the universe compared to other elements of nearby atomic weight. On Earth, fluorine is essentially found only in mineral compounds because of its reactivity.

Key takeaways

Origin and occurrence of fluorine belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Origin and occurrence of fluorine to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Origin and occurrence of fluorine from memory before moving on to harder problems.

Reference excerpt

Fluorine is relatively rare in the universe compared to other elements of nearby atomic weight. On Earth, fluorine is essentially found only in mineral compounds because of its reactivity. The main commercial source, fluorite, is a common mineral.

In the universe

At 400 ppb, fluorine is estimated to be the 24th most common element in the universe. It is comparably rare for a light element (elements tend to be more common the lighter they are). All of the elements from atomic number 6 (carbon) to atomic number 12 (magnesium) are hundreds or thousands of times more common than fluorine except for 11 (sodium). One science writer described fluorine as a "shack amongst mansions" in terms of abundance. Fluorine is so rare because it is not a product of the usual nuclear fusion processes in stars. And any created fluorine within stars is rapidly eliminated through strong nuclear fusion reactions—either with hydrogen to form oxygen and helium, or with helium to make neon and hydrogen. The presence of fluorine at all—outside of temporary existence in stars—is somewhat of a mystery because of the need to escape these fluorine-destroying reactions. Three theoretical solutions to the mystery exist: In type II supernovae, atoms of neon could be hit by neutrinos during the explosion and converted to fluorine. In Wolf-Rayet stars (blue stars over 40 times heavier than the Sun), a strong solar wind could blow the fluorine out of the star before hydrogen or helium could destroy it. Finally, in asymptotic giant branch (a type of red giant) stars, fusion reactions occur in pulses and convection could lift fluorine out of the inner star. Only the red giant hypothesis has supporting evidence from observations, fluorine cations have been found in planetary nebulae. In space, fluorine commonly combines with hydrogen to form hydrogen fluoride. (This compound has been suggested as a tracer to enable tracking reservoirs of hydrogen in the universe.) In addition to HF, monatomic fluorine has been observed in the interstellar medium. Fluorine cations have been seen in planetary nebulae and in stars, including the Sun.

On Earth

Fluorine is the thirteenth most common element in Earth's crust, comprising between 600 and 700 ppm of the crust by mass. Because of its reactivity, it is essentially only found in compounds.

Commercial sources Three minerals exist that are industrially relevant sources of fluorine: fluorite, fluorapatite, and cryolite.

Fluorite Fluorite (CaF2), also called fluorspar, is the main source of commercial fluorine. Fluorite is a colorful mineral associated with hydrothermal deposits. It is common and found worldwide. China supplies more than half of the world's demand and Mexico is the second-largest producer in the world. The United States produced most of the world's fluorite in the early 20th century, but its last mine, in Illinois, shut down in 1995. Canada also exited production in the 1990s. The United Kingdom has declining fluorite mining and has been a net importer since the 1980s.

Fluorapatite Fluorapatite (Ca5(PO4)3F) is mined along with other apatites for its phosphate content and is used mostly for production of fertilizers. Most of the Earth's fluorine is bound in this mineral, but because the percentage within the mineral is low (3.5%), the fluorine is discarded as waste. Only in the United States is there significant recovery. There, the hexafluorosilicates produced as byproducts are used to supply water fluoridation.

Cryolite Cryolite (Na3AlF6) is the least abundant of the three major fluorine-containing minerals, but is a concentrated source of fluorine. It was formerly used directly in aluminium production. However, the main commercial mine, on the west coast of Greenland, closed in 1987.

Minor occurrences Several other minerals, such as the gemstone topaz, contain fluoride. Fluoride is not significant in seawater or brines, unlike the other halides, because the alkaline earth fluorides precipitate out of water. Commercially insignificant quantities of organofluorines have been observed in volcanic eruptions and in geothermal springs. Their ultimate origin (from biological sources or geological formation) is unclear. The possibility of small amounts of gaseous fluorine within crystals has been debated for many years. One form of fluorite, antozonite, has a smell suggestive of fluorine when crushed. The mineral also has a dark black color, perhaps from free calcium (not bonded to fluoride). In 2012, a study reported detection of trace quantities (0.04% by weight) of diatomic fluorine in antozonite. It was suggested that radiation from small amounts of uranium within the crystals had caused the free fluorine defects.

Citations

Indexed references

Illustrations

Worked examples

Example 1 — a first encounter with Origin and occurrence of fluorine

Start with the simplest possible case. Write down what Origin and occurrence of fluorine claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Origin and occurrence of fluorine before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Origin and occurrence of fluorine ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Origin and occurrence of fluorine

In research: Origin and occurrence of fluorine appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Origin and occurrence of fluorine in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Origin and occurrence of fluorine is common in secondary-school and first-year university syllabi. It links to neighbouring topics Fluorine, Geochemistry, so understanding it makes those chapters shorter.
In everyday life: Look for Origin and occurrence of fluorine outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Origin and occurrence of fluorine in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Origin and occurrence of fluorine means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Origin and occurrence of fluorine out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Origin and occurrence of fluorine in simple terms?

Fluorine is relatively rare in the universe compared to other elements of nearby atomic weight. On Earth, fluorine is essentially found only in mineral compounds because of its reactivity.

Why does Origin and occurrence of fluorine matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Origin and occurrence of fluorine?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Origin and occurrence of fluorine.