UN/NA Number Reference

UN 2190: Oxygen difluoride, compressed

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 2190 is assigned the proper shipping name Oxygen difluoride, compressed in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 2.3 Toxic Gas material. Required label(s): 2.3, 5.1, 8.

Packing group indicates the degree of danger within a hazard class: PG I is high danger, PG II medium, PG III low. The proper shipping name, hazard class, UN number, and packing group together form the basic shipping description that must appear on shipping papers and, where required, on the package and placard.

Emergency Response (ERG Guide 124)

Hazards: TOXIC. Oxidizer. May accelerate fire. Corrosive. May cause severe burns.

Fire: Use water spray or fog. Do not use dry chemical or CO2. Cool containers.

Spill: Do not touch. Stop leak if safe. Keep combustibles away from spilled material.

Chemical and Physical Properties

Oxygen difluoride appears as a colorless poisonous gas with a strong peculiar odor. Highly toxic by inhalation. Corrosive to skin and eyes. Can explode on contact with water. Decomposes to toxic gaseous fluorine if heated to high temperature. Prolonged exposure of the containers to high heat may result in their violent rupturing and rocketing. Used as an oxidizer for propellants.

CAS Number: 7783-41-7

Molecular Formula: F2O

Molecular Weight: 53.996 g/mol

Color / Form: COLORLESS GAS; YELLOWISH-BROWN WHEN LIQUID

Odor: PECULIAR SMELL

Boiling Point: -230 F

Melting Point: -371 °F (NIOSH, 2024)

Specific Gravity: 1.90 at -224 C

Vapor Pressure: greater than 1 atm

Vapor Density: 1.88 (heavier than air)

Water Solubility: 0.02 %

Regulatory Data

OSHA PEL

TWA 0.05 ppm (0.1 mg/m 3 )

NIOSH REL

C 0.05 ppm (0.1 mg/m 3 )

IDLH

Special Provisions

49 CFR 172.102 special provision codes for this entry: 1, N86. These codes modify the general requirements (packaging, quantity limits, exceptions) for this specific material. Look up each code in 49 CFR 172.102 for the full text.

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Reference data compiled from the DOT Hazardous Materials Table (49 CFR 172.101), the 2024 Emergency Response Guidebook, and public chemical databases (PubChem, NIOSH, EPA). Always verify the correct shipping description against the current regulation and the manufacturer's SDS Section 14 before shipping.