English Safety Data Sheet Database 中文版 MSDS

Nitrogen trioxide

CAS No. 10544-73-7 | PubChem CID 61526
Section 1. Identification
Chemical NameNitrogen trioxide CAS No.10544-73-7
Synonymsnitrousanhydride; nitrogentrioxide Chinese Name三氧化二氮
Molecular FormulaN2O3 Molecular Weight76.02
UN No.2421 Data SourcePubChem (NIH/NLM)
GHS Hazard Classification
Signal Word DANGER
Pictograms GHS03 · Oxidizer GHS04 · Compressed Gas GHS05 · Corrosive GHS06 · Acute Toxic
Hazard Statements H270H280H310H330H314
Precautionary Statements P220P244P260P262P264P270P271P280P284P301+P330+P331P302+P352P302+P361+P354P304+P340P305+P354+P338P316P320P321P361+P364P363P370+P376P403P403+P233P405P410+P403P501

Section 2. Hazards Identification

H270 (100%): May cause or intensify fire; oxidizer [Danger Oxidizing gases]

H280 (100%): Contains gas under pressure; may explode if heated [Warning Gases under pressure]

H310+H330 (100%): Fatal in contact with skin or if inhaled [Danger Acute toxicity, dermal; acute toxicity, inhalation]

H310 (100%): Fatal in contact with skin [Danger Acute toxicity, dermal]

H314 (100%): Causes severe skin burns and eye damage [Danger Skin corrosion/irritation]

H330 (100%): Fatal if inhaled [Danger Acute toxicity, inhalation]

P220, P244, P260, P262, P264, P270, P271, P280, P284, P301+P330+P331, P302+P352, P302+P361+P354, P304+P340, P305+P354+P338, P316, P320, P321, P361+P364, P363, P370+P376, P403, P403+P233, P405, P410+P403, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 38 reports by companies from 1 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.

Section 4. First-Aid Measures

Excerpt from ERG Guide 124 [Gases - Toxic and/or Corrosive - Oxidizing]:

Refer to the "General First Aid" section. Specific First Aid: Clothing frozen to the skin should be thawed before being removed. (ERG, 2024)

General First Aid:

· Call 911 or emergency medical service.

· Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination.

· Move victim to fresh air if it can be done safely.

· Administer oxygen if breathing is difficult.

· If victim is not breathing:

-- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance.

-- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped with a one-way valve or other device).

-- If no pulse detected or no respiratory medical device available, provide continuous compressions. Conduct a pulse check every two minutes or monitor for any signs of spontaneous respirations.

· Remove and isolate contaminated clothing and shoes.

· For minor skin contact, avoid spreading material on unaffected skin.

· In case of contact with substance, remove immediately by flushing skin or eyes with running water for at least 20 minutes.

· For severe burns, immediate medical attention is required.

· Effects of exposure (inhalation, ingestion, or skin contact) to substance may be delayed.

· Keep victim calm and warm.

· Keep victim under observation.

· For further assistance, contact your local Poison Control Center.

· Note: Basic Life Support (BLS) and Advanced Life Support (ALS) should be done by trained professionals.

Specific First Aid:

· Clothing frozen to the skin should be thawed before being removed.

In Canada, an Emergency Response Assistance Plan (ERAP) may be required for this product. Please consult the shipping paper and/or the "ERAP" section.

Section 5. Fire-Fighting Measures

Excerpt from ERG Guide 124 [Gases - Toxic and/or Corrosive - Oxidizing]:

CAUTION: These materials do not burn but will support combustion. Some will react violently with water.

SMALL FIRE: Contain fire and let burn. If fire must be fought, water spray or fog is recommended. Water only; no dry chemical, CO2 or Halon®. Do not get water inside containers. If it can be done safely, move undamaged containers away from the area around the fire. Damaged cylinders should be handled only by specialists.

FIRE INVOLVING TANKS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Cool containers with flooding quantities of water until well after fire is out. Do not direct water at source of leak or safety devices; icing may occur. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks in direct contact with flames. For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn. (ERG, 2024)

Section 6. Accidental Release Measures

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.

· Keep unauthorized personnel away.

· Stay upwind, uphill and/or upstream.

· Many gases are heavier than air and will spread along the ground and collect in low or confined areas (sewers, basements, tanks, etc.).

· Ventilate closed spaces before entering, but only if properly trained and equipped.

· Do not touch or walk through spilled material.

· Keep combustibles (wood, paper, oil, etc.) away from spilled material.

· Stop leak if you can do it without risk.

· Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material.

· Do not direct water at spill or source of leak.

· If possible, turn leaking containers so that gas escapes rather than liquid.

· Prevent entry into waterways, sewers, basements or confined areas.

· Isolate area until gas has dispersed.

· Ventilate the area.

Excerpt from ERG Guide 124 [Gases - Toxic and/or Corrosive - Oxidizing]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area for at least 100 meters (330 feet) in all directions.

SPILL: See ERG Table 1 - Initial Isolation and Protective Action Distances on the UN/NA 2421 datasheet.

FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2024)

Immediate precautionary measure

· Isolate spill or leak area for at least 100 meters (330 feet) in all directions.

· See Table 1 - Initial Isolation and Protective Action Distances.

· If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions.

Small spill:

- ISOLATE in all directions: 60 m (200 ft)

Large spill:

- ISOLATE in all directions: 200 m (600 ft)

- PROTECT people from downwind during DAY time: 0.3 km (0.2 mi)

- PROTECT people from downwind during NIGHT time: 1.2 km (0.8 mi)

- PROTECT people from downwind during DAY time: 1.4 km (0.9 mi)

- PROTECT people from downwind during NIGHT time: 4.3 km (2.7 mi)

Section 7. Handling and Storage

Excerpt from ERG Guide 124 [Gases - Toxic and/or Corrosive - Oxidizing]:

Do not touch or walk through spilled material. Keep combustibles (wood, paper, oil, etc.) away from spilled material. Stop leak if you can do it without risk. Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material. Do not direct water at spill or source of leak. If possible, turn leaking containers so that gas escapes rather than liquid. Prevent entry into waterways, sewers, basements or confined areas. Isolate area until gas has dispersed. Ventilate the area. (ERG, 2024)

Section 8. Exposure Controls / Personal Protection

· Wear positive pressure self-contained breathing apparatus (SCBA).

· Wear chemical protective clothing that is specifically recommended by the manufacturer when there is NO RISK OF FIRE.

· Structural firefighters' protective clothing provides thermal protection but only limited chemical protection.

TIH (Toxic Inhalation Hazard) - Term used to describe gases and volatile liquids that are toxic when inhaled. Some are TIH materials themselves, e.g., chlorine, and some release TIH gases when spilled in water, e.g., chlorosilanes. [ERG 2016].

The compound is currently at the Holding Status AEGLs which have been reviewed by the NAC/AEGL Committee and are on hold due to insufficient data to develop AEGL values.

AEGLs Status: Holding

0.5 [ppm]

12 [ppm]

20 [ppm]

CAUTION: These materials do not burn but will support combustion. Some will react violently with water.

Small Fire

· Contain fire and let burn. If fire must be fought, water spray or fog is recommended.

· Water only; no dry chemical, CO2 or Halon®.

· Do not get water inside containers.

· If it can be done safely, move undamaged containers away from the area around the fire.

· Damaged cylinders should be handled only by specialists.

Fire Involving Tanks

· Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles.

· Cool containers with flooding quantities of water until well after fire is out.

· Do not direct water at source of leak or safety devices; icing may occur.

· Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank.

· ALWAYS stay away from tanks in direct contact with flames.

· For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn.

Excerpt from ERG Guide 124 [Gases - Toxic and/or Corrosive - Oxidizing]:

Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing that is specifically recommended by the manufacturer when there is NO RISK OF FIRE. Structural firefighters' protective clothing provides thermal protection but only limited chemical protection. (ERG, 2024)

Section 9. Physical and Chemical Properties

Nitrogen trioxide appears as a blue liquid with a sharp, unpleasant chemical odor. Density 1.447 g / cm3. Low-boiling (boiling point 3.5 °C) and held as a liquid by compression. Partially dissociates into NO and NO2. Strong irritant to skin, eyes and mucous membranes. Vapors very toxic by inhalation. Used in special purpose fuels. Under prolonged exposure to intense heat the container may rupture violently and rocket.

"Blue liquid with a sharp, unpleasant chemical odor"; [CAMEO]

-101.1 °C

1.4 @ 2°C

Gibbs energy

Schoenflies notation

Chemical bond

Chemical shift

Crystal structure

Crystallographic point group

Density functional theory

Enthalpy

Excitation energy

Formation energy

Formation enthalpy

Formation entropy

Gross formula

Heat capacity

Internuclear distance

Lattice stiffness

Lineshape

Microwaves

Molecular structure

Point group

Reaction coordinate

Space group

Symmetry axis

Transition enthalpy

Transition entropy

Toxic Gases & Vapors -> Oxidizers

Reactive agents - 1st degree

Section 10. Stability and Reactivity

No rapid reaction with air. No rapid reaction with water.

Oxidizing Agents, Strong

Strong Oxidizing Agent

NITROGEN TRIOXIDE is an oxidizing agent. Nonflammable but may cause fires when mixed with combustible materials. Reacts with reducing agents to generate heat and products that may be gaseous (causing pressurization of closed containers). The products may themselves be capable of further reactions (such as combustion in the air). Catalyzes ignition of phosphine gas [Edin. Roy. Soc. 13:88. 1935]. A mixture with caprolactam dissolved in acetic acid is explosive unless effectively cooled. Incompatible with phosphorus, or other reduced materials Reactivity likely to resemble that of nitrogen dioxide and nitrogen tetraoxide.

Section 11. Toxicological Information

Dermatotoxin - Skin burns.

Toxic Pneumonitis - Inflammation of the lungs induced by inhalation of metal fumes or toxic gases and vapors.

Section 14. Transport Information

Poison Gas Oxidizer Corrosive

Source: PubChem CID 61526 (NIH/NLM, public domain). Retrieved from PubChem, a public-domain chemistry database maintained by the U.S. National Library of Medicine. Last updated: 2026-08-02 09:19:41.
Disclaimer: This information is compiled for reference only and does not replace the manufacturer's official Safety Data Sheet. Always consult the supplier's SDS before handling any chemical.