UN/NA Number Reference
DOT Class 8 Corrosive placard

UN 2682: Cesium hydroxide

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 2682 is assigned the proper shipping name Cesium hydroxide 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 154)

Hazards: TOXIC. Corrosive. Non-combustible but may decompose producing toxic fumes when heated.

Fire: Use agent appropriate for surrounding fire. Cool containers.

Spill: Do not touch. Avoid inhalation. Use water spray to reduce fumes.

Chemical and Physical Properties

Cesium hydroxide is a colorless to yellow crystalline solid. Harmful to skin and eyes. Used in electric storage batteries.

CAS Number: 21351-79-1
Molecular Formula: CsHO
Molecular Weight: 149.913 g/mol
Color / Form: White-yellow hygroscopic crystals
Melting Point: 522 °F (NIOSH, 2024)
Specific Gravity: 3.68 (sinks in water)
Vapor Pressure: 0 mmHg (approx)
Water Solubility: 395 % at 59 F
pH: Strong alkaline reaction. The strongest base known

Regulatory Data

OSHA PEL
none
NIOSH REL
TWA 2 mg/m 3
IDLH
N

Special Provisions

49 CFR 172.102 special provision codes for this entry: IB8, IP2, IP4, T3, TP33. 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 2682 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.