Provenance

Reference data from EU CLP Annex VI and published regulations — verify against your supplier's SDS before use.

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Substance profile

Octamethylcyclotetrasiloxane

Octamethylcyclotetrasiloxane is an oily liquid.

CAS 556-67-2 Warning

01 · Identification

What Octamethylcyclotetrasiloxane is

Octamethylcyclotetrasiloxane is an oily liquid. It boils at 175 °C, melts at 17.5 °C.

Under the GHS it carries the signal word Warning.

CAS number556-67-2
EC number209-136-7
Index number014-018-00-1

Other names for Octamethylcyclotetrasiloxane

  • [D4]

02 · GHS classification

Hazards and label elements

Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.

Signal wordWarning
Hazard statements assigned to Octamethylcyclotetrasiloxane
CodeHazard statement
H361f Suspected of damaging fertility.
H410 Very toxic to aquatic life with long lasting effects.

Precautionary statements: P273, P391, P501

03 · Physical and chemical properties

Octamethylcyclotetrasiloxane properties

Every value is shown with the conditions it was measured under and the source it came from. Where sources disagree, all values are listed rather than one being picked — the difference is usually a different form of the substance, not an error.

Property Value Conditions Source
Boiling point 175 °C (347 °F) HSDB
175 °C (347 °F) at 760 mmHg DOE PAC
Melting point 17.5 °C (63.5 °F) HSDB
Density 0.9558 g/cm³ HSDB
0.96 g/cm³ ICSC
0.9558 g/cm³ at 25 °C DOE PAC
Solubility Soluble in carbon tetrachloride HSDB
In water, 0.056 mg/L at 23 °C at 23 °C HSDB
In synthetic seawater water, 0.033 mg/L at 25 °C at 25 °C HSDB
Vapor pressure 0.9998 mmHg at 21.7 °C ICSC
1.05 mmHg at 25 °C HSDB
1.05 mmHg Haz-Map
Flash point 55 °C (131 °F) HSDB
56 °C (132.8 °F) ICSC
Critical temperature and pressure 312.55 °C (594.6 °F) HSDB

Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.

04 · Handling and storage

Storing and handling Octamethylcyclotetrasiloxane

Storage conditions

Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed and kept upright to prevent leakage. Storage class (TRGS 510): Flammable liquids.

Source: Hazardous Substances Data Bank (HSDB)

Incompatible materials

Incompatible materials: Strong oxidizing agents, acids, bases.

Source: Hazardous Substances Data Bank (HSDB)

Planning storage for a mix of chemicals? Check Octamethylcyclotetrasilox… in the storage compatibility matrix →

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