Fluorine is highly reactive and the most electronegative element in the periodic table. It was discovered by Andre-Marie Ampere in 1810.
Discovery and History
The high reactivity and corrosive nature of fluorine led to delay in the discovery and isolation of fluorine as a distinct element. Several early experiments with fluorine caused serious health hazards to the scientist. However, in 1810 André-Marie Ampère, proposed that the unknown component of hydrofluoric acid is a distinct element that is analogous to chlorine. Later, Humphry Davy named the substance fluorine from fluoric acid and the suffix “-ine” used for all halogens . Long before its formal discovery, fluorine minerals were used in various laboratory and industrial settings. It was used for the smelting of ores and was named fluo, which is the Latin word for flow. The name fluorine was derived from its characteristic of flowing minerals. The symbol of fluorine is F, which is also derived from its Latin name which later became, fluorum.
Fluorine is the 13th most abundant element on Earth and is present in about 600 ppm by mass in the Earth’s crust . In universe, fluorine is the 24th most abundant element. Fluorine in elemental form quickly reacts with vapors present in the atmosphere and thus its elemental existence is almost nil. Fluorine does not exist in pure form but is present combined with minerals. In nature, the main source of fluorine is fluorite, cryolite and fluorapatite. Fluorite is the most abundant and China and Mexico are the largest suppliers of fluorite.
Fluorine is a pale yellow, diatomic gas. It has a pungent smell. At lower temperature (-188°C), fluorine can condense to bright yellow liquid. There are two solid forms of fluorine, α- and β-fluorine. β-fluorine is transparent and soft while α- fluorine is hard and opaque, and form at -220 °C and -228 °C, respectively. It is highly flammable. Fluorine can be fluorescent under certain conditions. In liquid form, fluorine is readily soluble in liquid oxygen and ozone .
Fluorine is highly reactive gas. It is highly corrosive in nature. Fluorine has the second highest electron affinity. Fluorine has the highest electronegativity among all elements. It has the third highest first ionization energy among all elements, that is why it is almost impossible to remove electrons from its valence shell. Fluorine forms very strong bonds with other elements. Cold fluorine gas can react with unreactive substances, such as glass, powdered steel. Water and wood can catch fire when exposed to pressurized fluorine. Alkali metals reacts vigorously with fluorine and can cause explosions. Gases, such as sulfur dioxide and hydrogen sulfide readily combine with fluorine. Fluorine reacts explosively with hydrogen gas. Oxygen does not react with fluorine at room temperatures. Halogens also readily react with fluorine .
Significance and Uses
- The largest consumption of fluorine is in the making of UF6 for nuclear fuel chain (fluorination of uranium tetrafluoride).
- A huge proportion of fluorine is used in the preparation of SF6 (an inert dielectric compound) that is used in making high-voltage transformers and circuit breakers.
- Various compounds of fluorine are used in various electronics, such as in cleaning equipment.
- Fluoride in the form of inorganic compounds is used in glass etching and steel picking.
- Organofluorides are used in making refrigerant gases (Freons) and surfactants. They are used as solvents, propellants and in air conditioning systems.
- Fluorine is used to make agrichemicals, including fungicides and herbicides.
- Fluorination of water has been done since 1940s to fight tooth decay.
- Fluorine-19, the stable isotope is used in magnetic resonance imaging (MRI).
- Fluroine-18 is used as a radioactive tracer in various tomographic techniques to detect tumors.
- Fluorine is present in various pharmaceuticals, such as Lipitor, that is a cholesterol reducing drug. Similarly, Seretide, an asthma prescription is a widely used drug and contain fluorinated compound called the, fluticasone which is as the active agent.
- Fluorine is used in making of various steroids and antibiotics.
Fluorine in elemental form is highly toxic to living organisms. It is considered more dangerous than hydrogen cyanide. Fluorine causes significant irritation in the respiratory system and eyes at about 100 ppm. Ingestion of fluorine can lead to liver and kidney damage. Ingestion of fluorine in concentration above 25ppm and inhalation of 1000 ppm is considered as potentially lethal dose . Hydrofluoric acid can lead to severe tissue damage upon inhalation, ingestion or direct contact. If enter in blood, it can adversely react with magnesium and calcium and lead to life threatening situation. Fluorine is also part of a notorious group of compounds, known as the chlorofluorocarbons (CFCs), which damage the ozone layer and are released in to the environment via various anthropogenic activities.
Isotopes of Fluorine
In nature, there is only one stable isotope of fluorine, fluorine-19. It is quite abundant and its magnetogyric ratio is quite high. There are seventeen artificial isotopes of fluorine, and their mass number range from 14 to 31. Fluorine-18 is the most stable artificial isotope. All other isotopes of fluorine are radioactive .
. Ampère 1816
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