UN/NA Number Reference
DOT Class 3 Flammable Liquid placard

UN 2749: Tetramethylsilane

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 2749 is assigned the proper shipping name Tetramethylsilane in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 3 Flammable Liquid material, Packing Group I. Required label(s): 3.

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 130)

Hazards: Flammable. Toxic vapor. Harmful if inhaled or absorbed. May accumulate in low areas.

Fire: Dry chemical, CO2, foam, water spray. Do not use straight streams.

Spill: Eliminate ignition sources. Stop leak. Absorb with sand/earth. Prevent waterway contamination.

Chemical and Physical Properties

Tetramethylsilane appears as a colorless, mildly acidic volatile liquid. A serious fire hazard. Mildly toxic by ingestion. Emits acrid smoke and fumes when heated to high temperatures. Less dense than water and insoluble in water, but soluble in most organic solvents. Used as an aviation fuel and as an internal standard for nmr analytical instruments.

CAS Number: 75-76-3
Molecular Formula: C4H12Si
Molecular Weight: 88.22 g/mol
Color / Form: Volatile liquid or gas
Boiling Point: 26.6 C
Melting Point: -99.06 °C
Flash Point: -27 dec C (closed cup)
Specific Gravity: 0.641 g/cu cm
Vapor Pressure: 718.0 [mmHg]
Water Solubility: Insoluble in cold concentrated sulfuric acid
Log P: log Kow = 3.24

Special Provisions

49 CFR 172.102 special provision codes for this entry: A7, T14, 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 2749 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.

Check the source: Current DOT Hazardous Materials Table · Official Emergency Response Guidebook. This compiled record is not a shipment classification or a complete response procedure.