Hexamethyldisiloxane

Hexamethyldisiloxane
Stereo structural formula of hexamethyldisiloxane
Ball-and-stick model of the hexamethyldisiloxane molecule
Names
Preferred IUPAC name
Hexamethyldisiloxane
Other names
  • Bis(trimethylsilyl) ether
  • Bis(trimethylsilyl) oxide
Identifiers
3D model (JSmol)
Abbreviations HMDSO, (TMS)2O
1736258
ChEBI
ChemSpider
ECHA InfoCard 100.003.176 Edit this at Wikidata
EC Number
  • 203-492-7
MeSH Hexamethyldisiloxane
RTECS number
  • JM9237000
UNII
UN number 1993
  • InChI=1S/C6H18OSi2/c1-8(2,3)7-9(4,5)6/h1-6H3 checkY
    Key: UQEAIHBTYFGYIE-UHFFFAOYSA-N checkY
  • InChI=1/C6H18OSi2/c1-8(2,3)7-9(4,5)6/h1-6H3
    Key: UQEAIHBTYFGYIE-UHFFFAOYAL
  • O([Si](C)(C)C)[Si](C)(C)C
Properties
C6H18OSi2
Molar mass 162.379 g·mol−1
Appearance Colourless liquid
Density 0.764 g·cm−3
Melting point −59 °C (−74 °F; 214 K)
Boiling point 100 to 101 °C (212 to 214 °F; 373 to 374 K)
930.7±33.7 ppb (23 °C) [1]
Vapor pressure 43 hPa (20 °C) [2]
1.377
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
  • Highly flammable liquid and vapour
  • Causes serious eye irritation
GHS labelling:
GHS02: FlammableGHS09: Environmental hazard[2]
Danger[2]
H225, H410[2]
P210, P233, P240, P273, P403+P235[2]
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g. propaneInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
4
0
Flash point −1(1) °C
Related compounds
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Hexamethyldisiloxane (HMDSO or MM) is an organosilicon compound with the formula O[Si(CH3)3]2. This volatile colourless liquid is used as a solvent and as a reagent in organic synthesis. It is prepared by the hydrolysis of trimethylsilyl chloride. The molecule is the protypical disiloxane and resembles a subunit of polydimethylsiloxane.

  1. ^ Sudarsanan Varaprath; Cecil L. Frye; Jerry Hamelink (1996). "Aqueous solubility of permethylsiloxanes (silicones)". Environmental Toxicology and Chemistry. 15 (8): 1263–1265. doi:10.1002/etc.5620150803.
  2. ^ a b c d e Record of Hexamethyldisiloxane in the GESTIS Substance Database of the Institute for Occupational Safety and Health, accessed on November 10, 2021.