Octamethylcyclotetrasiloxane
Also known as: OMCTS, Cyclotetrasiloxane, 2,2,4,4,6,6,8,8-octamethyl-, Dimethylsiloxane cyclic tetramer, Octamethylcyclotetrasiloxane, 98%, UC7207, Union Carbide 7207, VS7207
Octamethylcyclotetrasiloxane (CAS 556-67-2) is a compound in the Aliphatic Hydrocarbons category listed in the Jingsj chemical database. It has the molecular formula C8H24O4Si4 and a molecular weight of 296.616 g/mol. Key properties include a melting point of 17-18 °C(lit.), a boiling point of 175.0±0.0 °C at 760 mmHg, a density of 1.0±0.1 g/cm3 and a flash point of 63.2±23.0 °C. It is classified under GHS with signal word Warning and hazard statements H226 — Flammable liquid and vapour, H361 — Suspected of damaging fertility or the unborn child and H413. No supplier offers are currently listed; request a quote. Record last updated Aug 21, 2026.
- CAS No.
- 556-67-2
- Jingsj CID
- J-6739-5
- Molecular Formula
- C8H24O4Si4
- Molecular Weight
- 296.616 g/mol
- Category
- Aliphatic Hydrocarbons
- Last updated
- 8/21/2026
No offers for this compound yet.
Request a quotePhysicochemical Properties
| Melting Point | 17-18 °C(lit.) |
|---|---|
| Boiling Point | 175.0±0.0 °C at 760 mmHg |
| Density | 1.0±0.1 g/cm3 |
| Flash Point | 63.2±23.0 °C |
| Exact Mass | 296.075165 |
| PSA | 36.92000 |
| LogP | 2.87360 |
| Additional Property | 1 (vs air) |
| Vapor Pressure | 1.6±0.3 mmHg at 25°C |
| Refractive Index | 1.423 |
| Storage Conditions | 2-8°C |
| Additional Property | INSOLUBLE |
GHS Safety & Compliance
- H226 — Flammable liquid and vapour
- H361 — Suspected of damaging fertility or the unborn child
- H413
Frequently Asked Questions
What is the CAS number of Octamethylcyclotetrasiloxane?
The CAS number of Octamethylcyclotetrasiloxane is 556-67-2.
What are the molecular formula and molecular weight of Octamethylcyclotetrasiloxane?
Octamethylcyclotetrasiloxane has molecular formula C8H24O4Si4 and molecular weight 296.616 g/mol.
Is Octamethylcyclotetrasiloxane hazardous?
Octamethylcyclotetrasiloxane has GHS signal word Warning and hazard statements H226 — Flammable liquid and vapour; H361 — Suspected of damaging fertility or the unborn child; H413.
What are the upstream and downstream products of Octamethylcyclotetrasiloxane?
For Octamethylcyclotetrasiloxane, Upstream Products: Water, Dichlorodimethylsilane, Hexamethylcyclotrisiloxane; Downstream Products: Octamethyltrisiloxane, Decamethyltetrasiloxane, Dodecamethylpentasiloxane.
Data compiled from public chemical databases such as PubChem and supplier catalogs; supplier offers are provided by suppliers.
Last updated:
How to cite: Jingsj. "Octamethylcyclotetrasiloxane (CAS 556-67-2)". Jingsj Chemical Database. https://www.jingsj.com/compound/J-6739-5 (accessed 2026-11-06).
Data for reference only; verify product details with suppliers before purchase.