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chlorine

Also known as: CHLORINE · Molecular chlorine · 7782-50-5 · dichlorine

CAS No.: 7782-50-5
Formula: Cl2
Molar mass: 70.9 g/mol
PubChem CID: 24526

GHS pictograms

Oxidizing

Compressed gas

Corrosive

Toxic

Harmful / Irritant

Health hazard

Environmental hazard

2D structure of chlorine — 2D structure · PubChem CID 24526

Summary

chlorine (Cl2), CAS 7782-50-5. Common in labs and industry. Read on for hazards, storage, PPE and mixing rules.

Background

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Hazards

Oxidizing (GHS03)

May cause or intensify fire.

Compressed gas (GHS04)

Contents under pressure, may explode if heated.

Corrosive (GHS05)

Attacks skin, eyes and materials.

Toxic (GHS06)

May be fatal even in small doses.

Harmful / Irritant (GHS07)

May cause skin, eye or respiratory irritation.

Health hazard (GHS08)

Serious long-term health effects (CMR, respiratory sensitizer).

Environmental hazard (GHS09)

Toxic to aquatic organisms.

Hazard statements

H270: May cause or intensify fire
H315: Causes skin irritation [Warning Skin corrosion/irritation]
H319: Causes serious eye irritation [Warning Serious eye damage/eye irritation]
H331: Toxic if inhaled [Danger Acute toxicity, inhalation]
H335: May cause respiratory irritation [Warning Specific target organ toxicity, single exposure
H400: Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]
H280: Contains gas under pressure
H330: Fatal if inhaled [Danger Acute toxicity, inhalation]
H410
H314: Causes severe skin burns and eye damage [Danger Skin corrosion/irritation]
H318: Causes serious eye damage [Danger Serious eye damage/eye irritation]
H370: Causes damage to organs [Danger Specific target organ toxicity, single exposure]

Storage

Temperature

Keep at room temperature, below 30 °C, out of direct heat.

Ventilation

Store somewhere well-ventilated and away from any ignition source.

Containers

Metal drums or tinted glass, tightly sealed.

Keep away from

Strong acids, strong bases and powerful oxidizers.

Personal protective equipment

Gloves

Nitrile or butyl, at least 0.4 mm thick.

Eye protection

Safety goggles with side shields.

Respirator

A2 organic-vapor cartridge if the room isn't well ventilated.

Occupational exposure limits (HSE)

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EU harmonised classification (ECHA C&L)

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Transport

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FDA recalls & enforcement

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Compatibilities

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Practical safety notes

Oxidizing. Keep away from combustibles, organics, reducers and fuels.
Compressed gas. Secure cylinders upright, protect valves, store in ventilated areas.
Corrosive. Wear chemical goggles, faceshield and chemical-resistant gloves. Have an eyewash within reach.
Acute toxicity. Work under a fume hood, restrict access, keep a specific antidote plan available.
Irritant / harmful. Ventilate the workspace and avoid skin contact.
Serious health hazard (carcinogen, mutagen, reprotoxic, respiratory sensitizer). Substitute if possible; otherwise closed systems and medical surveillance.
Environmental hazard. Do not release to sewers or waterways; collect for hazardous waste disposal.

Derived from the GHS classification shown above. These notes are generic guidance and do not replace the manufacturer's SDS or your local risk assessment.

FAQ

Is chlorine flammable?+

chlorine (CAS 7782-50-5) does not carry the GHS02 flame pictogram in our records. Always confirm with the manufacturer's SDS section 9 (flash point) before assuming a product is non-flammable.

What PPE should I wear when handling chlorine?+

Chemical-splash goggles and a faceshield, chemical-resistant gloves (nitrile or butyl) and an apron are the minimum. Work inside a fume hood or use a suitable respirator. Check SDS section 8 for material-specific breakthrough times.

How should chlorine be stored?+

Store chlorine (CAS 7782-50-5) in tightly closed original containers, in a cool, dry, well-ventilated area away from incompatible materials. Segregate acids from bases and keep away from metals that can be attacked.

Is chlorine dangerous for the environment?+

Yes. chlorine carries the GHS09 environment pictogram. Do not release to drains, soil or waterways; collect residues for hazardous-waste disposal in line with local regulations.

Where can I find the official Safety Data Sheet for chlorine?+

Official, up-to-date SDS documents are published by each manufacturer (Sigma-Aldrich, Merck, Thermo Fisher, VWR, Carl Roth, etc.) and by regulators such as ECHA and NIOSH. This page is an educational summary and does not replace the manufacturer's SDS.

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