F

Fluorine

F₂ CAS 7782-41-4
Quick Reference
Formula / NotationF₂
CAS Number7782-41-4
Molecular Weight38.00 g/mol
Melting Point−219.67°C (53.48 K)
Boiling Point−188.11°C (85.04 K)
Density1.696 g/L at STP
AppearancePale yellow-green diatomic gas with a pungent, sharp odor
Also Known AsFluorine gas, Difluorine

What is Fluorine?

The most electronegative element, with atomic number 9 and symbol F. It is a pale yellow, highly reactive diatomic gas (F₂) and the lightest halogen. Fluorine forms compounds with almost all elements. It is used in refrigerants, non-stick coatings (PTFE), and toothpaste.

Formula & Notation

F₂

Other Names / Synonyms: Fluorine gas, Difluorine

Properties & Characteristics

Atomic number 9. Group 17 (halogens), Period 2. Most electronegative element (Pauling scale: 3.98). Strongest oxidizing agent known. Forms compounds with almost all elements including noble gases (XeF₂, XeF₄). Bond energy F−F = 159 kJ/mol (unusually weak due to lone pair repulsion). Standard reduction potential E°(F₂/F⁻) = +2.87 V.

Physical Data

PropertyValue
Melting Point−219.67°C (53.48 K)
Boiling Point−188.11°C (85.04 K)
Density1.696 g/L at STP
Molecular Weight38.00 g/mol
AppearancePale yellow-green diatomic gas with a pungent, sharp odor

Uses & Applications

Production of uranium hexafluoride (UF₆) for uranium isotope enrichment in nuclear fuel. Manufacture of fluoropolymers: PTFE (Teflon), PVDF. Etching silicon and glass in semiconductor manufacturing. Refrigerants (CFCs, HFCs, HFOs). Toothpaste and water fluoridation (as NaF or fluorosilicates). Antireflective coatings on lenses. Sulfur hexafluoride (SF₆) for electrical insulation.

Safety Information

EXTREMELY HAZARDOUS. Fluorine gas is violently toxic — PEL = 0.1 ppm, IDLH = 25 ppm. Contact with skin causes deep chemical burns (hydrofluoric acid burns are especially dangerous — calcium gluconate antidote required). Reacts explosively with organic materials, water, and most metals. Requires specialized stainless steel or monel equipment with full respiratory protection and face shield. Store and handle only by trained personnel in dedicated facilities.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Fluorine
Formula F₂
CAS Number 7782-41-4
Molecular Weight 38.00 g/mol
Synonyms Fluorine gas, Difluorine

Frequently Asked Questions

The most electronegative element, with atomic number 9 and symbol F. It is a pale yellow, highly reactive diatomic gas (F₂) and the lightest halogen. Fluorine forms compounds with almost all elements. It is used in refrigerants, non-stick coatings (PTFE), and toothpaste.

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