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.

02 · Identifiers

Octamethylcyclotetrasiloxane identifiers and molecular data

Octamethylcyclotetrasiloxane CAS number and EC number

CAS number556-67-2
EC number209-136-7
Index number (CLP Annex VI)014-018-00-1

Other names for Octamethylcyclotetrasiloxane

  • [D4]

03 · GHS classification

Octamethylcyclotetrasiloxane hazard classification

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

Octamethylcyclotetrasiloxane pictograms and signal word

Signal wordWarning

Octamethylcyclotetrasiloxane hazard class and category

GHS hazard classes Octamethylcyclotetrasiloxa… falls into
Hazard class Category From code Pictogram
Hazardous to the aquatic environment - chronic GHS chapter 4.1 Category 1 H410 GHS09

Octamethylcyclotetrasiloxane hazard statements (H-codes)

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

This page lists only the codes assigned to Octamethylcyclotetrasiloxa…. The full reference lives on the hazard statements hub, the precautionary statements hub and the GHS pictograms hub.

Safety Data Sheet

Getting an SDS for Octamethylcyclotetrasiloxa…

A Safety Data Sheet is written for a product, not for a substance: the supplier of the grade you actually buy issues it, so two suppliers of Octamethylcyclotetrasi… issue two different sheets. That is why there is no single authoritative SDS for a substance to download — what there is, is the job of collecting the sheets for the products you hold and keeping them current as suppliers revise them.

04 · Precautionary statements

Octamethylcyclotetrasiloxane precautionary statements

CLP Annex VI assigns 3 precautionary statements to Octamethylcyclotetrasiloxa…. They are grouped the way a label groups them: what to do before handling, what to do when something has already happened, how to store it and how to dispose of it.

Prevention

What to do before and during handling so the hazard never happens.

Response

What to do once exposure, spillage or fire has already happened.

Disposal

What has to happen to the contents and the empty container.

Reading the notation. is a blank the supplier fills in — not a truncated sentence.· [square brackets] mark a part printed only when it applies.

05 · Names in the regulation

Octamethylcyclotetrasiloxane name in 23 EU languages

CLP Annex VI Part 3 is published in every language edition of the regulation, and the identification column is written out in each of them. Nothing below is translated by us: each line is the name as that edition prints it. Under Art. 18(2) the substance name from Annex VI is a lawful product identifier, so this is the wording to put on a label going to that market — and where the cell lists several designations, any one of them qualifies.

Language Name in CLP Annex VI Part 3
Bulgarian български октаметилциклотетрасилоксан
Spanish español Octametilciclotetrasiloxano
Czech čeština oktamethylcyklotetrasiloxan
Danish dansk octamethylcyclotetrasiloxan
German Deutsch Octamethylcyclotetrasiloxan
Estonian eesti Oktametüültsüklotetrasiloksaan
Greek ελληνικά οκταμεθυλοκυκλοτετρασιλοξάνιο
English English octamethylcyclotetrasiloxane
French français octaméthylcyclotétrasiloxane
Croatian hrvatski oktametilciklotetrasiloksan
Italian italiano ottametilciclotetrasilossano
Latvian latviešu oktametilciklotetrasiloksāns
Lithuanian lietuvių oktametilciklotetrasiloksanas
Hungarian magyar oktametilciklotetrasziloxán
Maltese Malti ottametilċiklotetrasiloksan
Dutch Nederlands octamethylcyclotetrasiloxaan
Polish polski oktametylocyklotetrasiloksan
Portuguese português octametilciclotetrassiloxano
Romanian română octametilciclotetrasiloxan
Slovak slovenčina oktametylcyklotetrasiloxán
Slovenian slovenščina oktametilciklotetrasiloksan
Finnish suomi oktametyylisyklotetrasiloksaani
Swedish svenska oktametylcyklotetrasiloxan

All 23 language editions of Annex VI carry this entry. Irish is the twenty-fourth official EU language and has no line here for a different reason: no consolidated CLP text has ever been published in Irish, so there is no Irish edition of Annex VI to quote a name from. Source: consolidated CLP, CELEX 02008R1272, language editions. © European Union, https://eur-lex.europa.eu — only the electronic Official Journal of the European Union is authentic.

06 · Label elements

Octamethylcyclotetrasiloxane GHS label elements

Everything CLP Annex VI fixes for Octamethylcyclotetrasiloxa…, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.

GHS08 Health hazard pictogramGHS09 Environment pictogram

Warning

Octamethylcyclotetrasiloxane

  • Suspected of damaging fertility.
  • Very toxic to aquatic life with long lasting effects.
  • Avoid release to the environment.
  • Collect spillage.
  • Dispose of contents/container to

Supplier name, address and telephone number· Product identifier·Nominal quantity

Need this as an actual label? Open Octamethylcyclotetrasiloxa… in the GHS label constructor →

07 · Health hazards

Octamethylcyclotetrasiloxane health hazards and exposure limits

Octamethylcyclotetrasiloxane hazard summary

No listed effects of short-term or long-term exposure; Can be absorbed through skin; [ICSC] Volunteers were exposed to 10 ppm for 1 hour and then again 3 months later; No immunotoxic or inflammatory effects were detected; Silicones cause foreign body reactions when injected or implanted in tissues; [HSDB] An irritant; [MSDSonline]

Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases

08 · 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.

Octamethylcyclotetrasiloxane boiling point

Property Value Conditions Source
Boiling point 175 °C (347 °F) HSDB
175 °C (347 °F) at 760 mmHg DOE PAC

Octamethylcyclotetrasiloxane melting point

Property Value Conditions Source
Melting point 17.5 °C (63.5 °F) HSDB

Octamethylcyclotetrasiloxane density

Property Value Conditions Source
Density 0.9558 g/cm³ HSDB
0.96 g/cm³ ICSC
0.9558 g/cm³ at 25 °C DOE PAC

Octamethylcyclotetrasiloxane solubility

Property Value Conditions Source
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

Octamethylcyclotetrasiloxane vapor pressure

Property Value Conditions Source
Vapor pressure 0.9998 mmHg at 21.7 °C ICSC
1.05 mmHg at 25 °C HSDB
1.05 mmHg Haz-Map

Octamethylcyclotetrasiloxane flash point

Property Value Conditions Source
Flash point 55 °C (131 °F) HSDB
56 °C (132.8 °F) ICSC

Octamethylcyclotetrasiloxane critical temperature and pressure

Property Value Conditions Source
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.

09 · Handling and storage

Octamethylcyclotetrasiloxane storage 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)

Octamethylcyclotetrasiloxane 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 →

10 · Questions

Octamethylcyclotetrasiloxane — frequently asked questions

What is the CAS number of Octamethylcyclotetrasiloxane?

The CAS number of Octamethylcyclotetrasiloxane is 556-67-2. Its EC number is 209-136-7.

What does a Octamethylcyclotetrasiloxane label have to show?

Under CLP Annex VI the label for Octamethylcyclotetrasiloxane carries the pictograms Health hazard and Environment and the signal word is Warning.

Is Octamethylcyclotetrasiloxane flammable?

CLP Annex VI assigns Octamethylcyclotetrasiloxane no flammability hazard class. That is not a statement that it cannot burn: the harmonised list only records the hazards that were assessed for it. The flash point reported for it is 55 °C (131 °F) (HSDB).

Is Octamethylcyclotetrasiloxane a carcinogen?

CLP Annex VI records no harmonised carcinogenicity classification for Octamethylcyclotetrasiloxane. Annex VI is a list of agreed classifications, not a list of substances found safe, so this is an absence of a classification rather than a clean bill of health.

What is the boiling point of Octamethylcyclotetrasiloxane?

The boiling point reported for Octamethylcyclotetrasiloxane is 175 °C (347 °F) (HSDB).

What is the melting point of Octamethylcyclotetrasiloxane?

The melting point reported for Octamethylcyclotetrasiloxane is 17.5 °C (63.5 °F) (HSDB).

How should Octamethylcyclotetrasiloxane be stored?

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. (Hazardous Substances Data Bank (HSDB))

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