Fluorine was isolated by Henri Moissan in 1886, although its compounds, such as fluorspar, cryolite, and fluorapatite, were used in various applications for centuries.
The element’s highly reactive nature made it difficult to isolate. Moissan achieved this through the electrolysis of dry potassium bifluoride (KHF₂) dissolved in anhydrous hydrofluoric acid (HF). His successful isolation of fluorine won him the Nobel Prize in Chemistry in 1906.
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- Symbol: F
- Atomic Number: 9
- Atomic Weight: 18.998403163
- Element Classification: Halogen
- Discovered By: Henri Moissan
- Discovery Date: 1886
- Name Origin: Latin: ‘fluere’ (to flow)
- Density(g/cc): 0.001696 (at 0°C, 101.325 kPa)
- Melting Point: -219.67°C
- Boiling Point: -188.11°C
- Appearance: Pale yellow gas
- Atomic Radius(pm): 50
Relation to Other Elements
Fluorine is the most electronegative and reactive of all elements. It is located in Group 17 of the periodic table, known as the halogens. Fluorine’s reactivity is such that it forms compounds with all other elements except for some noble gases under certain conditions. It is characterized by its ability to form strong bonds with other atoms, especially carbon, which results in highly stable fluorocarbons with unique properties such as high thermal and chemical stability. The element plays a crucial role in many organic and inorganic chemical reactions, particularly in the substitution and addition reactions due to its high reactivity.
Natural Occurrence
Fluorine is found in the Earth’s crust, primarily in the form of fluorite (CaF₂), cryolite (Na₃AlF₆), and apatite (Ca₅(PO₄)₃(F,Cl,OH)). It is the thirteenth most abundant element in the crust. Naturally occurring fluorine is entirely of the isotope fluorine-19. Despite its abundance, fluorine does not exist in its elemental form in nature due to its high reactivity but is instead found in compound forms.
Uses
The applications of fluorine and its compounds are varied and significant:
- Chemical Industry: Fluorine is used in the synthesis of numerous compounds including pharmaceuticals and agrochemicals. Fluorinated compounds are used in refrigerants, blowing agents, and in the manufacture of polymers like Teflon (PTFE).
- Dentistry and Medicine: Fluoride, the anion of fluorine, is added to dental products and water supplies to prevent dental cavities. Fluorine-18 is a radioactive isotope used in positron emission tomography (PET) scans in diagnostic imaging.
- Nuclear Energy: Uranium hexafluoride (UF₆) is used in the process of uranium enrichment, which is critical for producing fuel for nuclear reactors and nuclear weapons.
- Optics and Electronics: Fluorine compounds are used in the production of low-refractive-index glass and in the cleaning of silicon surfaces in the semiconductor industry.
- Refrigeration: Fluorocarbons, particularly chlorofluorocarbons (CFCs) were used as refrigerants and propellants before their phase-out due to their ozone-depleting effects.
The discovery and subsequent industrial utilization of fluorine have had profound impacts on modern science and technology, offering advancements in healthcare, materials science, and energy. However, the handling and use of fluorine and its compounds require strict safety measures due to their high reactivity and potential toxicity.