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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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Transport classification per the UN Model Regulations / 49 CFR 172.101 Hazardous Materials Table. Confirm against the grade-specific SDS (Section 14) before shipping.
Octamethyltrisiloxane (MDM) is a linear trisiloxane with a viscosity of approximately 1 cSt at 25°C. It is slightly longer chain than hexamethyldisiloxane (0.65 cSt) and is used as an intermediate in silicone polymer production, as a chain stopper, and as a volatile carrier fluid in industrial formulations.
Regulatory & registration requirements
- TSCA (US):
- REACH (EU):
- EC number: 203-497-4
Source: EPA TSCA Inventory (July 2025 release) · ECHA CHEM — retrieved 2026-07-12
Regulatory restriction status
Octamethyltrisiloxane (MDM) (CAS 107-51-7) appears on the regulatory list(s) below. This is public regulatory information about the substance — not a statement about any specific supplier’s material, and not a safety claim. Confirm the current status for your jurisdiction and intended use.
- REACH SVHC Candidate List (EU): listed 21 Jan 2025 on the basis of vPvB (Art. 57(e)). SVHC status triggers EU supplier-communication and notification duties above 0.1% w/w; it is not, by itself, a ban on sale.
Sources: ECHA Candidate List / Annex XIV / Annex XVII (echa.europa.eu); U.S. EPA TSCA; UN Stockholm Convention / EU POPs Regulation; California OEHHA Proposition 65 list. Retrieved 2026-07-13.
Frequently Asked Questions
What is octamethyltrisiloxane?
Octamethyltrisiloxane (MDM, CAS 107-51-7, formula C8H24O2Si3) is the simplest linear trisiloxane, a low-viscosity volatile silicone fluid. It belongs to the silicone fluids and oils family and is the M-D-M trisiloxane member of the methyl siloxane series.
What is the density of octamethyltrisiloxane?
Octamethyltrisiloxane is a low-density, low-viscosity liquid at room temperature, with a density on the order of about 0.82 g/cm3. Refer to the SDS and CoA for the exact specification of the supplied lot.
What is octamethyltrisiloxane used for?
As a volatile, low-viscosity silicone fluid it is used as a carrier and spreading solvent and as a viscosity-reducing diluent for higher-viscosity silicone fluids in industrial and formulated silicone systems.
How does MDM relate to other silicone fluids?
MDM is the three-unit linear methyl siloxane; longer-chain analogs build the polydimethylsiloxane fluid series. Its short chain gives the low viscosity and volatility that distinguish it from higher-molecular-weight silicone oils.
What is the cost of bulk octamethyltrisiloxane?
Bulk pricing depends on volume, packaging (drums, totes, or IBCs), and freight; request a current quote with your quantity and destination. A CoA and SDS are provided with bulk orders.
What is the REACH and TSCA regulatory status of Octamethyltrisiloxane (MDM)?
Octamethyltrisiloxane (MDM) (CAS 107-51-7) is subject to U.S. TSCA Inventory requirements; supplying it into the EU requires valid REACH registration ((EC) No 1907/2006). RawSource cannot verify a third-party supplier's registrations — buyers should require documented TSCA and REACH compliance for their jurisdiction and volume (EC 203-497-4).