UN/NA Number Reference
DOT Class 8 Corrosive placard

UN 3498: Iodine monochloride, liquid

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 3498 is assigned the proper shipping name Iodine monochloride, liquid in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 8 Corrosive material, Packing Group II. Required label(s): 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 137)

Hazards: Produce flammable gases on contact with water. May ignite on contact with water. Some react violently with water.

Fire: DO NOT use water or foam. Use dry chemical, dry sand, or soda ash.

Spill: Do not touch. Keep material dry. Move containers from water. Dike to prevent water contact.

Chemical and Physical Properties

Iodine monochloride appears as black crystals or a reddish brown oily liquid with a pungent odor. Melting point 27 °C (alpha form) or 14 °C (beta form). Corrosive to metals and tissue.

CAS Number: 7790-99-0
Molecular Formula: ClI
Molecular Weight: 162.36 g/mol
Color / Form: BLACK CRYSTALS OR REDDISH-BROWN LIQ
Boiling Point: 207 F
Melting Point: ALPHA 27.2; BETA 13.9 °C
Specific Gravity: 3.10
Water Solubility: SOL IN WATER, ALC, ETHER, CARBON DISULFIDE, ACETIC ACID

Special Provisions

49 CFR 172.102 special provision codes for this entry: IB2, T7, TP2. 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.

Need the full interactive record? Open UN 3498 in the SpillNerd lookup tool for the live database entry with placard graphics, GHS pictograms, full segregation tables, and synonym search. For another material, use the UN number and chemical lookup.

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.