Fluorine F (Element 9) of Periodic Table

09 F (Fluorine Element)

About Fluorine

Fluorine is very pale yellow-green, corrosive gas, which reacts with most organic and inorganic substances. It is most Electronegative and dangerously reactive of all elements and quickly attacks all metals.
 
Fluorine readily form compounds with most other elements, even with the noble gases Xenon, Krypton and Radon.
 
It is so reactive that glass, metals, ceramics, carbon, and even water, as well as other substances, burn with a bright flame.
 
In aqueous solution (Ex: Sodium chloride (Na⁺ + Cl^–) in water), fluorine commonly occurs as the fluoride ion F^–. Fluorides (F^–) are compounds that combine fluoride with some positively charged counterpart.
 
Before World War II, there was no commercial production of elemental fluorine, But after using it in Nuclear bomb project and nuclear energy application, made it necessary to produce large quantities.

Identity
CAS Number: CAS7782-41-4
CID Number:  CID24524
DOT Hazard Class:  2.3
DOT Number:  9192
RTECS Number:  RTECSLM6475000

Basic Properties of Fluorine

Pronunciation:  (Floor-een / in / yn) (Flohr-een / in / yn)
Appearance:  Very pale yellow (In Gas), Bright yellow (in Liquid), Alpha (α) is Opaque & Beta (β) is transparent (in Solid)
Allotropes: Alpha (α), Beta (β)
Mass Number:  19
Standard Atomic weight: 18.998  g/mol
Atomic number (Z):  9
Electrons:  9
Protons:  9
Neutrons:  10
Period:  2
Group:  17
Block:  p
Element category:  Halogens
Electrons per shell:  K2, L7
Electron configuration:  1s²2s²2p⁵

Thermal Properties of Fluorine

Phase:  Gas
Melting point:  58.49 K (-219.67 ^oC, -363.41 ^oF)
Boiling point:   85.03 K (-88 ^oC, -306.6 ^oF)
Triple point Temperature:  53.48 K (-219.67 ^oC, -363.406 ^oF)
Triple point Pressure:  90 kPa (0.888231 Atm)
Critical point Temperature:  144.41 K (-128.74 ^oC, -199.732 ^oF)
Critical point Pressure:  5.172 MPa (51.04 Atm)
Fusion heat:  0.26 kJ/mol
Vaporization heat:  6.51 kJ/mol
Specific heat:  824 J/(kg K)
Molar heat capacity:  31 J/(mol.K) (C_p), 23 J/(mol.k) (C_v)
Thermal conductivity:  0.02591 W/(m∙K)

Physical Properties of Fluorine

Density:  1.695 g/L (At STP)  1.5.5 g/cm (In Liquid at M.P)
Molar volume:  0.011202 m³/mol
Sound Speed:  2130 m/s

Atomic Properties of Fluorine

Oxidation states:  -1
Valence Electrons:  4f⁶ 6s²
Ion charge:  F^–
The ionization potential of an atom: 18.6 eV
Ionization energies:  1st: 1681 kJ.mol 2nd: 3374 kJ/mol 3rd: 6147 kJ/mol
Ionic radius:  1.33 pm
Atomic radius:  57 pm (empirical)
Van der Waals:  135 Pm
Covalent radius:  64 pm
Filling Orbital:  2p⁵
Crystal structure:  Cubic
Lattice angles:  π/2, π/2, π/2
Lattice constant:  550, 328, 728 pm
Grid parameters:  a=5.50 Å, b=3.28 Å, c=7.28 Å, (β=102.17°)
Attitude c/a:
Space Group Name:  C12/c1
Space Group Number:  15

Reactivity of Fluorine

Electronegativity:  3.98 (pauling scale)
Valence:  -1 (+1)
Electron affinity:  328 kJ/mol

Nuclear Properties of Fluorine

Half Life:  Stable (Infinity)
Lifetime:  Stable (Infinity)
Quantum Number:  ²P_3/2
Neutron cross section (Brans):  0.0096
Neutron Mass Absorption:  0.00002
Isotopes:   18_F 19_F
 

Isotope	Abundance (%)	Atomic Mass g/mol	Half Life (t1/2)
18F	Trace	–	109.8 (min)
19F	100	18.997	Stable

Chemical Reactions of Fluorine

Reaction With Air

Fluorine is not particularly reactive towards with oxygen or Nitrogen, but it reacts with moisture in air and forms oxygen (O₂)
2 F₂ (g) + 2 H₂O (g) → O₂ (g) + 4 HF (g)

Reaction With Water

Fluorine reacts with water to produce Oxygen (O₂) and Ozone (O₃)
2 F₂ (g) + 2 H₂O (l) → O₂ (g) + 4 HF (aq)
Or
F₂ (g) + H₂O (l) → O₂ (g) + OF₂ (aq) + H₂O₂ (aq) + HF (aq)
 
3 F₂ (g) + 3 H₂O (l) → O₃ (g) + 6 HF (aq)
Reacts with Frozen water
F₂ (g) + H₂O → HOF (g) + HF (g)

Reaction With Halogens

F₂ reacts with chlorine, at 225 °C and formed the interhalogen species Chlorine fluoride (CIF), the trifluoride chloride (III) fluoride is also formed but the reaction doesn’t go to completion.
Cl₂ (g) + F₂ (g) → 2 CIF (g)    (Chlorine fluoride)
Cl₂ (g) + 3 F₂ (g) → 2 CIF₃ (g)    (Chloride trifluoride)
Under more forcing conditions, excess F₂ reactswith Chlorine at 350 ^oC and 225 Atm (Atmospheres pressure) and formed the interhalogen species CIF₅ (Chlorine pentafluoride).
Cl₂ (g) + 5 F₂ (g) → 2  CIF₅ (g)    (Chlorine pentafluoride)
(F₂) reacts with Bromine (Br₂), in the gas phase it formed the interhalogen species (BrF), It is difficult to obtain pure since BrF disproportionates at room temp. to form bromine, Bromine trifluoride (BrF₃) & Bromine pentafluoride (BrF₅).
Br₂ (g) + F₂ (g) → 2 BrF (g)
3 BrF (g) → Br₂ (l) + BrF₃ (l)
5 BrF (g) → 2 Br₂ (l) + BrF₅ (l)
Under more forcing conditions, excess F₂ reacts with Bromine at 150 ^oC and formed the interhalogen species BrF₅.
Br₂ (l) + 5 F₂ (g) → 2 BrF₅ (l)
Elemental Fluorine reacts with iodine (I₂) at -45 ^oC in CCl₃F solvent and forms the interhalogen species Iodine fluoride (IF), It is difficult to obtain pure since IF (Iodine fluoride) disproportionates at room temp. to form iodine (I₂) and Iodine pentafluoride (IF₅).
I₂ (g) + F₂ (g) → 2 IF (g)
5 IF (g) → 2 I₂ (s) + IF₅ (l)

Reaction With Acids

The element reacts with dilute Acids, the reaction is probably dominated by the water, which produces Oxygen (O₂) and Ozone (O₃).
2 F₂ (g) + 2 H₂O (l) → O₂ (g) + 4 HF (aq)
3 F₂ (g) + 3 H₂O (l) → O₃ (g) + 6 HF (aq)

Reaction With Bases

The element reacts with dilute Aqueous hydroxide solutions to form oxygen (II) fluoride.
2 F₂ (g) + 2 OH^– (aq) → OF₂ (g) + 2 F^– (aq) + H₂O (l)

Reaction With Hydrogen

F₂ Reacts quickly with Hydrogen, and forms hydrogen fluoride (HF), This is dangerous reaction and can be explosive under the right conditions.
H₂ (g) + F₂ (g) → 2 HF (g)

Reaction With Noble Gasses

Krypton will react with fluorine at -196 ^oC and zapped with an electric discharge or X-rays, to forms krypton difluoride (KrF₂).
Kr (s) + F₂ (s) → KrF₂ (s)
This compound again decomposes when it comes to room temperature.
 
Xenon (Xe) can be brought to react with fluorine (F₂), and forms xenon fluorides
1Xe (g) + 2 F₂ (g) → XeF₄ (s), mix gasses at 400 ^oC then cool to -78 ^oC
Xe (g) + F₂ (g) → XeF₂ (s)
Xe (g) + 3 F₂ (g) → XeF₆ (s)
The xenon fluorides are used for synthesis of other xenon compounds.
 
Radon can be brought to react with Fluorine, But the exact formula for the molecule is unknow, so usually it written as RnF_n.

Fluorine History

Naming:  After the mineral fluorite, itself named after Latin fluo (flow)
Discovery:  André-Marie Ampère (1810)
First isolation:  Henri  Moissan (1886)
Named by:  Humphry Davy

Fluorine Uses

Fluorine and its compounds are used in producing uranium hexafluoride (UF₆), needed by the nuclear power industry to separate uranium isotopes.
 
It is also used to make sulfur hexafluoride(SF₆), the insulating gas for high-power electricity transformers and more than 100 commercial fluorochemicals, including solvents and high-temperature plastics, such as Teflon (polytetrafluoroethene, (C₂F₄)_n), PTFE), and in halons such as Freon (freon), in the production of uranium.
 
Teflon is well known for its non-stick properties and is used in frying pans, It is also used for plumber’s tape, for cable insulation, and used in waterproof shoes and clothing.
 
Atomic and molecular fluorine are used for plasma etching in semiconductor manufacturing, flat panel display production and MEMs (Micro-Electro-Mechanical Systems) fabrication. Hydrofluoric acid (HF) is used for etches glass of light bulbs.
 
Hydro-Chloro-Fluoro-carbons (HCFCs) are extensively used in air conditioning and refrigeration.
Fluorides are often added to Toothpaste to prevent dental cavities.
 
HCFCs is better than CFCs, Because HCFCs are less stable in the lower atmosphere and usually break down in the troposphere before reaching the stratosphere (ozone layer) and attacking the ozone, But CFCs diffuse into the stratosphere and destroys the Earth’s ozone layer, so it is now banned.
 
Elemental fluorine has been studied as a rocket propellant as it has an exceptionally high specific impulse value.

Biological role

Elemental fluorine and the fluoride ion are highly toxic, At low concentrations it causes eye and nose irritations, but it can cause death at very high concentrations.
Above 25 PPM – Irritation of the eyes and respiratory system as well as Occurring damage the liver and kidney.
At 100 PPM – Eyes and noses are seriously damaged.
Inhalation of 1000 PPM – Death in minutes. (this quantity can compare to 270 PPM for Hydrogen cyanide)
 
Metal fluorides are also very toxic while organic fluorides are often quite harmless.
 
Fluoride is also an essential ion for human and animals for strengthening teeth and bones. it also present in drinking water in some areas. Level of fluoride below 2 PPM (2 mg/L) in drinking water is good to prevent dental cavities, if it is applied through toothpaste twice a day. Above this concentration level, it may cause children’s tooth enamel to become mottled.
 
If fluorine is absorbed too much, then it can cause teeth decay, osteoporosis, and harm to bones, kidneys, nerves, and muscles.
 
Humans are exposure to fluorine through Food, Drinking water and by Breathing air. The safe working level should be as low as 20 ppb (0.02 mg/L), and the recommended maximum allowable  concentration is 1 ppm (Parts per million) for a daily 8-hour time-weighted exposure.
 
The average human body contains about 3 mg (milligrams) of fluoride, and too much fluoride could be toxic.

Abundance of Fluorine 

Fluorine occurs naturally in the earth’s crust, and can be found in form of Rocks, Clay and Coal.
It is the 13th most common element in the Earth’s crust: approx 950 ppm is contained in it.
Soils contain approximately 330 ppm (Parts Per Million) of fluorine, ranging from 200 to 400 ppm.
Some soils can have as much as 1000 ppm and contaminated soils have been found with 3500 ppm.
 
Hydrogen fluorides (HF) are released into the air through combustion processes in the industry.
Fluorides that are found in the air eventually drop onto the land or water, but when fluorine is attached in very small particles, then it remains in the air for a long period of time.
 
In the atmosphere 0.6 ppb (Parts per billion) or 0.0006 ppm (parts per million) of fluorine are present as salt spray and organic chloride compounds, and upto 50 ppb in the city.
 
Fluorine is widely distributed in many minerals, but the most common minerals are Fluorite or Fluorspar (Calcium fluoride, CaF₂), Cryolite (Na₂AlF₆) and Fluorapatite (Calcium fluorophosphates, Ca₅(PO₄)₃F).

It is produced by the electrolysis of a solution of potassium hydrogendi-fluoride (KHF₂) in anhydrous hydrofluoric acid (HF).

TDS (Total Dissolved Solids)

Generally, People think that TDS meter measure how much fluoride in water, but the truth is that the TDS meter shows the Total Dissolved Solids (charged ions, include minerals, salts or metals (Calcium, Fluoride, Magnesium, Chlorides, Sulphates, Potassium and Sodium etc…)) concentration in water, which measures in mg/Litre (PPM).

Taste of Water With Different TDS Concentration
Level of TDS (mg/litre) or (PPM)	Rating
Below 30	Harmful
Less than 300	Excellent
300 – 600	Good
600 – 900	Fair
900 – 1200	Poor
Above 1200	Unacceptable
1000 – 10,000	Brackish water
More  than 10, 000	Saline water
More than 35, 000	Sea water (Very salty / Brine water)

Annual world wide production of Fluorine gas is around 3,700 tons, and fluorite is around 6,500,000 tons.
0.00004% (In Universe)
0.0087% (In Meteorites)
0.00005% (In Sun)
0.054% (In Earth’s Crust)
0.00013% (In Oceans)
0.0037% (In Humans)

World’s Top 3 producers of Fluorine

1) China
2) Mexico
3) Mongolia

World’s Top 3 Reserve holders of Fluorine

1) South Africa
2) Mexico
3) China

Fluorine Price
Pure (99.99%) element price is around  $1700-$1900 per KG (KiloGram)

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