DISILOXANE- ▸ 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
GHS02
GHS07
GHS08
GHS09
- H225 Highly flammable liquid and vapor
- H315 Causes skin irritation
- H332 Harmful if inhaled
- H372 Causes damage to organs through prolonged or repeated exposure
- H410 Very toxic to aquatic life with long lasting effects
- P210 Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
- P233 Keep container tightly closed.
- P240 Ground and bond container and receiving equipment.
- P241 Use explosion-proof electrical, ventilating and lighting equipment.
- P242 Use non-sparking tools.
- P243 Take action to prevent static discharges.
- P261 Avoid breathing dust, fume, gas, mist, vapours or spray.
- P264 Wash hands and exposed skin thoroughly after handling.
- P271 Use only outdoors or in a well-ventilated area.
- P273 Avoid release to the environment.
- P280 Wear protective gloves, protective clothing, eye protection and face protection.
- P303+P361+P353 IF ON SKIN (or hair) — Take off immediately all contaminated clothing — Rinse skin with water or shower.
- P304+P340 IF INHALED — Remove person to fresh air and keep comfortable for breathing.
- P370+P378 In case of fire — Use appropriate media to extinguish.
- P391 Collect spillage.
- P403+P235 Store in a well-ventilated place — Keep cool.
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 (MM / HMDSO)?
Hexamethyldisiloxane (CAS 107-46-0), known in the silicone trade as MM or HMDSO, is the shortest linear siloxane — two trimethylsilyl groups joined by an oxygen bridge. It is the lowest-viscosity member of the silicone fluid range at about 0.65 cSt at 25°C, highly volatile, and used as a chain stopper in PDMS production, a fast-drying carrier and a laboratory solvent.
Is MM fluid the same as 0.65 cSt silicone fluid?
Yes. MM (hexamethyldisiloxane) is the discrete molecule sold as the 0.65 cSt grade — the volatile bottom of the dimethicone viscosity ladder. Because it is a single defined molecule rather than a polymer, its properties are fixed (MW 162.38, boiling point ~99-100°C) rather than varying by grade.
What is the molecular formula and weight of Hexamethyldisiloxane?
Molecular formula C6H18OSi2, molecular weight 162.38 g/mol. IUPAC name: trimethyl(trimethylsilyloxy)silane. InChIKey: UQEAIHBTYFGYIE-UHFFFAOYSA-N. PubChem CID 24764.
Is Hexamethyldisiloxane (MM) hazardous?
Yes — GHS signal word Danger. It is a highly flammable liquid (H225; flash point about -30°C) and is classified for skin irritation and aquatic toxicity. Ship and store as a flammable; a current grade-specific SDS ships with every order.
Identity and hazard data sourced from PubChem and authoritative regulatory references. Confirm against the grade-specific CoA and SDS supplied with every shipment.