Silicone Fluids & Oils Available — Bulk Only

Hexamethyldisiloxane (MM, HMDSO)

HMDSO
CAS 107-46-0 · Formula C6H18OSi2 · MW 162.38 g/mol · EC 203-492-7

Hexamethyldisiloxane (MM / HMDSO, CAS 107-46-0) is the shortest linear siloxane and the most volatile silicone fluid, at about 0.65 cSt — sold in the trade as MM fluid. It acts as a chain stopper in PDMS manufacture, a fast-evaporating carrier in personal care, and a low-residue industrial solvent.

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UN Number
UN 1993
Hazard Class
Class 3
HS Code
2931.90
At a Glance
Material Family
Silicone Fluids & Oils
Record Type
Pure compound
Primary Role
Solvency · Slip / Release
Physical State
Volatile liquid
Appearance
Clear, colorless, low-viscosity fluid
Functional Roles
Applications & Use Cases
  • Silicone intermediate: chain stopper capping chain length in polydimethylsiloxane (PDMS) manufacture
  • Volatile carrier: fast-evaporating spreading agent for antiperspirants, lotions and hair care
  • Process solvent: low-residue cleaning solvent for electronics and coatings
  • Mold release: carrier and release fluid for industrial molding
Physical Properties
Viscosity
0.65 cSt @ 25C
Density
0.764 g/mL @ 20C
Boiling point
99-100 C
Melting point
-66 C
Flash point
-30 C (closed cup)
Solubility in water
0.93 mg/L @ 25C
Vapor pressure
42 mmHg @ 25C
PDMS Viscosity Ladder — All Grades (cSt @ 25 °C)

Don’t see your viscosity? We can custom-formulate silicone fluid to your target cSttell us your spec.

Bulk packaging: 55-gal drums · 275-gal IBC totes · 5-gal pails
Safety & Handling
Full SDS available on request

A grade-specific Safety Data Sheet (SDS) — with the complete hazard classification, handling precautions, and transport information — is supplied with every shipment and available on request. Confirm all safety and regulatory details against the SDS for your specific grade.

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DOT / UN Transport Classification
DOT hazard class 3 placard
UN / DOT NumberUN 1993
Hazard Class / DivisionClass 3
Proper Shipping NameFlammable liquids, n.o.s.

Transport classification per the UN Model Regulations / 49 CFR 172.101 Hazardous Materials Table. Confirm against the grade-specific SDS (Section 14) before shipping.

HS / Tariff Classification
Harmonized System (HS) Code — 6-digit international heading
2931 . 90
Chapter 29
Organic chemicals
Heading 29.31
Internationally harmonized (WCO HS)
Subheading 2931.90
6-digit international code — national tariff line adds further digits
Chemical Identity
CAS Number
107-46-0
EC / EINECS
203-492-7
Molecular Formula
C6H18OSi2
Molecular Weight
162.38 g/mol
IUPAC Name
trimethyl(trimethylsilyloxy)silane
INCI Name
DISILOXANE
PubChem CID
InChI Key
UQEAIHBTYFGYIE-UHFFFAOYSA-N
XLogP
5.2
H-Bond Donor / Acceptor
0 / 1
Synonyms & Trade Names
MM MM Fluid MM Silicone HMDSO Hexamethyldisiloxane Disiloxane Bis(trimethylsilyl)ether
Full Description

Hexamethyldisiloxane (MM / HMDSO, CAS 107-46-0) is the shortest linear siloxane and the most volatile silicone fluid, at roughly 0.65 cSt. Sold in the trade as MM fluid, it serves as a chain stopper that caps chain length in polydimethylsiloxane (PDMS) manufacture, as a fast-evaporating carrier and spreading agent in personal care, and as a low-residue solvent in industrial and laboratory use. It is the volatile bottom of the silicone viscosity ladder; the next grades up are MDM (1 cSt) and MD2M (1.5 cSt). RawSource supplies MM fluid in bulk, sourced to spec, with CoA and SDS on every order.

Frequently Asked Questions

What is hexamethyldisiloxane used for?

Hexamethyldisiloxane (HMDSO/MM, CAS 107-46-0) is a low-viscosity, volatile silicone fluid used as a carrier solvent and viscosity reducer in silicone and personal-care formulations and as a building-block intermediate in the synthesis of silicone polymers. RawSource supplies it in bulk to silicone and formulation manufacturers.

Is hexamethyldisiloxane a silicone?

Yes. Hexamethyldisiloxane is the simplest siloxane, with a silicon-oxygen-silicon backbone and six methyl groups (C6H18OSi2). It is the basic structural unit underlying larger silicone fluids and polymers.

Is hexamethyldisiloxane water soluble?

No, hexamethyldisiloxane is a hydrophobic siloxane and is essentially insoluble in water; it is miscible with organic solvents and functions as a volatile carrier in non-aqueous systems. See the SDS and technical data sheet for solvency and volatility data.

How is hexamethyldisiloxane shipped, given its UN number?

Hexamethyldisiloxane is a flammable liquid assigned UN 1993, so it ships under DOT/IATA/IMDG hazardous-materials rules with appropriate packaging and labeling. RawSource supplies the SDS with each order; confirm packaging and mode requirements with your carrier.

How is bulk hexamethyldisiloxane packaged and quoted?

RawSource ships HMDSO as a bulk liquid in DOT-compliant drums and totes for silicone and personal-care accounts. Pricing depends on volume, packaging, and hazmat freight; submit an RFQ with your quantity and ship-to for a current quote with CoA and SDS.

Disclaimer. Information on this page — including properties, identifiers, hazard, transport (DOT/UN) and tariff (HS) classifications, and applications — is provided for general reference and is compiled from authoritative public sources (e.g. PubChem/ECHA, 49 CFR 172.101, the Harmonized Tariff Schedule). Values are typical and are not a guaranteed specification; the Certificate of Analysis (CoA) for the lot purchased governs. Products are sold for industrial and professional use only. Nothing here is a medical, health, or efficacy claim or advice. Always consult the current Safety Data Sheet (SDS) before handling, storage, transport or disposal, and confirm regulatory status, classification and suitability for your application and jurisdiction. Hazard, transport and tariff classifications must be verified for your specific shipment. RawSource makes no warranty, express or implied, and assumes no liability for use of this information. Trademarks. Third-party trademarks and brand names are the property of their respective owners; any reference is nominative — used only to identify a comparable product — and does not imply affiliation with, sponsorship by, or endorsement by the trademark owner.