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What is Fluorine

Denoted by the chemical symbol F, fluorine (pronounced as FLU-eh-reen) is a highly reactive nonmetal existing naturally in the state of gas. When it gains an electron from another atom in a reaction, it forms fluoride whose ion symbol is F– [11].It belongs to the family of halogens, reacting with almost all metals, having a lesser electron affinity than chlorine. It exists as a diatomic molecule, represented by the molecular formula F2.

Fluorine Symbol

What are its Common Isotopes

It has 11 isotopes with mass numbers ranging from 15 to 25 of which only F-19 has a stable life.

Where is the Element Commonly Found

The thirteenth most abundant element in earth’s crust, it is associated with several mineral sources like fluorspar, cryolite, and fluorite present in the mining areas of Mexico, China, and Western Europe [1].

Fluorine Electron (Lewis) Dot Diagram


Origin of its Name: Its name is derived from the Latin word ‘flure’ that means to flow.

Who Discovered it: Henri Moissan

When, Where, and How was the Element Discovered

Many chemists had speculated the presence of an unknown element having properties similar to chlorine in metal fluorides. In fact, Humphry Davy, a Cornish chemist, while trying to isolate it from hydrochloric acid, fell ill.

In 1869, the British chemist George Gore passed an electric current through liquid hydrogen fluoride (HF) and produced a highly reactive gas. Despite knowing it to be the suspected element, he could not prove it. It was only in 1886 when Moissan extracted it through electrolysis of potassium bifluoride dissolved in liquid HF and became the founder.

Fluorine Crystal Rock


Atomic number 9 [1]
CAS number 7782-41-4 [1]
Position in the periodic table [1] Group Period Block
17 2 p

Where is Fluorine Located on the Periodic Table

Classification, Properties and Characteristics of Fluorine

General Properties

Relative/Average atomic mass 18.998 [1]
Atomic mass/weight 18.998 atomic mass units [5]
Molar mass/Molecular weight 37.9968064± 0.0000010 g/mol [6]
Mass number 19

Physical Properties

Color/physical appearance Pale yellow-green [1]
Texture Unknown [13]
Odor Pungent [3]
Melting point/freezing point -219.67°C (363.41°F) [1]
Boiling point -188.11°C (306.6°F)  [1]
Density 0.001553 g/cm3 [1]
Hardness Unknown [13]
Malleability No [14]
Standard/Physical state of matter at room temperature (solid/liquid/gas) Gas [1]
Solubility Highly soluble in water [4]
Electrical conductivity Unknown [3]
Thermal conductivity 0.0277 Wm-1K-1 [3]

Chemical Properties

Flammability Flammable [3]
Oxidation state/Oxidation number -1[1]

Atomic Data of Fluorine (Element 19)

Fluorine Orbital (Energy) Level Diagram

Valence electrons 7 [8]
Electron configuration (noble gas configuration) [He] 2s22p5[1]
Atomic structure [8]
– Number of Electrons 9
– Number of Neutrons 10
– Number of Protons 9
Radius of atom
– Atomic radius 1.47 Å [1]
– Covalent radius 0.60 Å [1]
Electronegativity 3.98 [10]
Ion charge +7 [9]
Ionization energy [1]


1st 2nd 3rd 4th 5th 6th 7th
1681.045 3374.17 6050.441 8407.713 11022.755 15164.128 17867.734

Fluorine Atomic Structure (Bohr Model Diagram)

What is it Commonly Used for

  • It is useful in the preparation of uranium hexafluoride to separate uranium isotopes in nuclear power plants.
  • The diatomic gas is added to poly(tetrafluoroethene) and high-temperature plastics required in the making of cable insulations, water bottles, plumber’s tape, frying pans, and water-proof fabric membranes for shoes and clothing.
  • It condenses into a bright yellow liquid that is used as a cryogenic agent [12].
  • Fluorine is the most important ingredient in toothpastes and mouthwashes as it helps in removing dental plaques and preventing cavity formation. It is also added to public drinking water in many countries for the same reason [2].
  • Rubbers with high fluorine content have a greater strength and resistance to wear and tear that make them effective as sealing components in engines of aircrafts, cars, and rockets [16].
  • Polymers of F-containing monomers added to resin paints and coatings are applied on surfaces of steel plates, pots, kettles, and some heat-resistant machine parts [17].
  • Lithium-fluorine batteries are useful for their higher durability [15].
  • Fluorine doped tin oxide coated glass slides find application in the manufacture of optic fibers and electronics.
  • Its use in absorption dating aids in detecting the amount of time an object has been lying underground such as ancient fossils [18].
  • F-containing compounds are effective markers in magnetic resonance imaging applications to detect any abnormality in the body [7].

Does the Element Have Any Toxic Hazards

Prolonged exposure to the skin and eyes can cause burns and irritation. When accidentally inhaled, it can affect the lungs. Repeated exposure may have severe health effects like diarrhea, constipation, nosebleeds, and kidney and liver damage [19].

Fluorine Gas

Interesting Facts

  • It is one of the few elements to form a layer on diamonds [14].
  • F is the most reactive and electronegative of all elements [20].

Fluorine Cost

Pure fluorine is priced somewhere between $190 and $200 per 100 grams.



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