A

Argon

IUPAC: Argon

Ar Elements CAS 7440-37-1
Quick Reference
Formula / NotationAr
CAS Number7440-37-1
Molecular Weight39.95
Melting Point-189.4
Boiling Point-185.8
Density0.00178
Solubility69.8 mg/L at 20 C
AppearanceColourless, odourless monatomic gas
Also Known AsAr, argon gas
CategoryElements

What is Argon?

Argon is a colourless, odourless noble gas, atomic number 18, the most abundant noble gas in Earth atmosphere (0.934%). Chemically inert with no known stable compounds. Produced by fractional distillation of liquid air.

Formula & Notation

Ar

IUPAC Name: Argon

Other Names / Synonyms: Ar, argon gas

Properties & Characteristics

Atomic number: 18. Atomic mass: 39.948 g/mol. Period 3, Group 18 (noble gas). Boiling point: -185.8 C. Melting point: -189.4 C. Density: 1.78 g/L (STP). Chemically inert. Isotopes: Ar-36, Ar-38, Ar-40 (99.6%).

Physical Data

PropertyValue
Melting Point-189.4
Boiling Point-185.8
Density0.00178
Molecular Weight39.95
Solubility69.8 mg/L at 20 C
AppearanceColourless, odourless monatomic gas

Uses & Applications

Inert shielding gas for TIG/MIG welding. Inert atmosphere for reactive metal production. Incandescent lighting filler. Argon lasers. Double-glazing insulation. Wine preservation. Semiconductor manufacture.

Safety Information

Asphyxiation hazard in enclosed spaces - displaces oxygen without warning. Cryogenic liquid argon (-186 C): cold burns. Pressurised cylinders: mechanical hazard. Otherwise non-toxic.

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

Key Facts

Term Argon
Formula Ar
CAS Number 7440-37-1
Molecular Weight 39.95
Category Elements
Synonyms Ar, argon gas

Frequently Asked Questions

Argon is a colourless, odourless noble gas, atomic number 18, the most abundant noble gas in Earth atmosphere (0.934%). Chemically inert with no known stable compounds. Produced by fractional distillation of liquid air.

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