UN/NA Number Reference
DOT Class 2.3 Toxic Gas placard

UN 2189: Dichlorosilane

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 2189 is assigned the proper shipping name Dichlorosilane 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, 2.1, 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 119)

Hazards: TOXIC. May be fatal if inhaled or absorbed through skin. Flammable. Vapors heavier than air.

Fire: Small: dry chemical or CO2. Large: water spray or fog. Fight from maximum distance.

Spill: Do not touch. Stop leak if safe. Use water spray to reduce vapor.

Chemical and Physical Properties

Dichlorosilane is a 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. Under prolonged exposure to fire or intense heat the container may rupture violently or rocket.

CAS Number: 4109-96-0
Molecular Formula: Cl2H2Si
Molecular Weight: 101.00 g/mol
Boiling Point: 8Â C
Melting Point: -122 °C
Flash Point: -28Â °C c.c.
Vapor Pressure: Vapor pressure, kPa at 20Â C: 163.6
Vapor Density: 3.48 (heavier than air)
Water Solubility: Solubility in water: reaction

Special Provisions

49 CFR 172.102 special provision codes for this entry: 2, B9, B14. 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 2189 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.