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Chemical Datasheet

CHLORINE MONOXIDE

Chemical Identifiers

CAS Number UN/NA Number DOT Hazard Label USCG CHRIS Code
  • 7791-21-1
 none data unavailable none
NIOSH Pocket Guide International Chem Safety Card
none none
NFPA 704
Diamond Hazard Value Description
4
3 3
Blue Health 3 Can cause serious or permanent injury.
Red Flammability 4 Burns readily. Rapidly or completely vaporizes at atmospheric pressure and normal ambient temperature.
Yellow Instability 3 Capable of detonation or explosive decomposition or explosive reaction but requires a strong initiating source or must be heated under confinement before initiation.
White Special
(NFPA, 2010)
General Description
Red-yellow gas. Very reactive and unstable. Unusually stored as hydrate in frozen form. Used as a wood bleach, biocide and swimming pool treatment.

Hazards

Reactivity Alerts
Air & Water Reactions
Decomposes in water forming chlorine and oxygen gases.
Fire Hazard
No information available.
Health Hazard
No information available.
Reactivity Profile
Explodes when heated or by reaction with organic materials, including: carbon, carbon disulfide, ethers, hydrocarbons, dicyanogen, any readily oxidizable materials (ammonia, potassium, arsenic, antimony, sulfur, mercury sulfide, calcium phosphide, phosphine, phosphorus, hydrogen sulfide, antimony sulfide, barium sulfide, mercury sulfide, and tin sulfide). Dissolves in alkalis, forming a mixture of chlorite and chlorate. Concentration of gas should be limited to less than 10% to reduce explosion hazard. Alcohols are oxidized explosively.
Belongs to the Following Reactive Group(s)
Potentially Incompatible Absorbents

Use caution: Liquids with this reactive group classification have been known to react with the absorbents listed below.

Response Recommendations

Isolation and Evacuation
No information available.
Firefighting
No information available.
Non-Fire Response
No information available.
Protective Clothing
No information available.
DuPont Tychem® Suit Fabrics
No information available.
First Aid
No information available.

Physical Properties

Chemical Formula:
  • Cl2O
Flash Point: data unavailable
Lower Explosive Limit (LEL): data unavailable
Upper Explosive Limit (UEL): data unavailable
Autoignition Temperature: data unavailable
Melting Point: data unavailable
Vapor Pressure: data unavailable
Vapor Density (Relative to Air): data unavailable
Specific Gravity: data unavailable
Boiling Point: data unavailable
Molecular Weight: data unavailable
Water Solubility: data unavailable
Ionization Energy/Potential: data unavailable
IDLH: data unavailable

AEGLs (Acute Exposure Guideline Levels)

No AEGL information available.

ERPGs (Emergency Response Planning Guidelines)

No ERPG information available.

PACs (Protective Action Criteria)

No PAC information available.

Regulatory Information

EPA Consolidated List of Lists

Regulatory Name CAS Number/
313 Category Code		 EPCRA 302
EHS TPQ		 EPCRA 304
EHS RQ		 CERCLA RQ EPCRA 313
TRI		 RCRA
Code		 CAA 112(r)
RMP TQ
Chlorine monoxide 7791-21-1 10000 pounds
Chlorine oxide 7791-21-1 10000 pounds

(EPA List of Lists, 2022)

CISA Chemical Facility Anti-Terrorism Standards (CFATS)

RELEASE THEFT SABOTAGE
Chemical of Interest CAS Number Min Conc STQ Security
Issue		 Min Conc STQ Security
Issue		 Min Conc STQ Security
Issue
Chlorine monoxide; [Chlorine oxide] 7791-21-1 1.00 % 10000 pounds flammable

(CISA, 2007)

OSHA Process Safety Management (PSM) Standard List

No regulatory information available.

Alternate Chemical Names