UN/NA Number Reference
DOT Class 2.1 Flammable Gas placard

UN 2203: Silane

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 2203 is assigned the proper shipping name Silane in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 2.1 Flammable Gas material. Required label(s): 2.1.

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 116)

Hazards: May polymerize explosively when heated or involved in fire. Extremely flammable. BLEVE risk.

Fire: Fight fire from maximum distance. Do not extinguish unless flow stopped. Cool containers with water.

Spill: Eliminate all ignition sources. Stop leak if safe.

Chemical and Physical Properties

Silane is a colorless, flammable and poisonous gas, with a strong repulsive odor. It is easily ignited in air, reacts with oxidizing agents, is very toxic by inhalation, and is a strong irritant to skin, eyes and mucous membranes. Silane is lighter than air. Under prolonged exposure to fire or heat the containers may rupture violently and rocket. It is used in the production of amorphous silicon.

CAS Number: 7803-62-5
Molecular Formula: H4Si
Molecular Weight: 32.117 g/mol
Color / Form: Colorless gas
Odor: Repulsive odor
Boiling Point: -169 F
Melting Point: -301 °F (NIOSH, 2024)
Flash Point: NA (Gas)
Autoignition: Pyrophoric
Specific Gravity: 0.68 at -185 C (liquid)
Vapor Pressure: greater than 1 atm
Vapor Density: 1.11 (heavier than air)
Water Solubility: Decomposes

Regulatory Data

OSHA PEL
none
NIOSH REL
TWA 5 ppm (7 mg/m 3 )
IDLH
N

Need the full interactive record? Open UN 2203 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.