C

Chlorine

IUPAC: Dichlorine

Cl2 Elements CAS 7782-50-5
Quick Reference
Formula / NotationCl2
CAS Number7782-50-5
Molecular Weight70.9
Melting Point-101.5
Boiling Point-34.1
Density0.00321
Solubility7.3 g/L at 20 C
AppearanceYellow-green diatomic gas; liquid is amber-coloured
Also Known AsCl2, chlorine gas
CategoryElements

What is Chlorine?

Chlorine is a yellow-green diatomic halogen gas, atomic number 17, with pungent suffocating odour. Powerful oxidising agent and disinfectant. Used as chemical warfare agent in WWI. Most produced by electrolysis of brine.

Formula & Notation

Cl2

IUPAC Name: Dichlorine

Other Names / Synonyms: Cl2, chlorine gas

Properties & Characteristics

Atomic number: 17. Atomic mass: 35.453 g/mol. Period 3, Group 17 (halogen). Boiling point: -34.1 C. Melting point: -101.5 C. Density: 3.21 g/L (STP). Electronegativity: 3.16. Isotopes: Cl-35 (75.8%), Cl-37 (24.2%). IDLH: 10 ppm.

Physical Data

PropertyValue
Melting Point-101.5
Boiling Point-34.1
Density0.00321
Molecular Weight70.9
Solubility7.3 g/L at 20 C
AppearanceYellow-green diatomic gas; liquid is amber-coloured

Uses & Applications

Drinking water and pool disinfection. PVC plastic production. HCl production. Bleach (NaOCl). Pharmaceutical synthesis. Solvents (CHCl3, DCM). Pesticides. Paper bleaching.

Safety Information

Toxic gas: TLV-C 1 ppm, IDLH 10 ppm. Severe respiratory damage, eye/mucous membrane irritation, pulmonary oedema. Chemical warfare agent. Never mix bleach with ammonia (toxic chloramines). Requires SCBA at high concentrations.

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

Key Facts

Term Chlorine
Formula Cl2
CAS Number 7782-50-5
Molecular Weight 70.9
Category Elements
Synonyms Cl2, chlorine gas

Frequently Asked Questions

Chlorine is a yellow-green diatomic halogen gas, atomic number 17, with pungent suffocating odour. Powerful oxidising agent and disinfectant. Used as chemical warfare agent in WWI. Most produced by electrolysis of brine.

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