Provenance

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

Build a label

Substance profile

Hexachlorocyclopentadiene

Hexachlorocyclopentadiene is a dense, oily liquid with a pungent, unpleasant odor.

CAS 77-47-4 C5Cl6 272.8 g/mol Danger

01 · Identification

What Hexachlorocyclopentadiene is

Hexachlorocyclopentadiene is a dense, oily liquid with a pungent, unpleasant odor. Its molecular formula is C5Cl6 and its molecular weight is 272.8 g/mol. It boils at 239 °C, melts at -9 °C.

Under the GHS it carries the signal word Danger. It is classed as hazardous Air Pollutants (HAPs).

02 · Identifiers

Hexachlorocyclopentadiene identifiers and molecular data

Hexachlorocyclopentadiene CAS number and EC number

CAS number77-47-4
EC number201-029-3
Index number (CLP Annex VI)602-078-00-7

Hexachlorocyclopentadiene molecular formula and molecular weight

Molecular formulaC5Cl6
Molecular weight272.8 g/mol
Chemical class Hazardous Air Pollutants (HAPs)

03 · GHS classification

Hexachlorocyclopentadiene hazard classification

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

Hexachlorocyclopentadiene pictograms and signal word

Signal wordDanger

Hexachlorocyclopentadiene hazard class and category

GHS hazard classes Hexachlorocyclopentadiene falls into
Hazard class Category From code Pictogram
Acute toxicity - oral GHS chapter 3.1 Category 4 H302 GHS07
Acute toxicity - dermal GHS chapter 3.1 Category 3 H311 GHS06
Acute toxicity - inhalation GHS chapter 3.1 Category 1 or 2 H330 GHS06
Skin corrosion/irritation GHS chapter 3.2 Category 1A or 1B or 1C H314 GHS05
Hazardous to the aquatic environment - acute GHS chapter 4.1 Category 1 H400 GHS09
Hazardous to the aquatic environment - chronic GHS chapter 4.1 Category 1 H410 GHS09

Where two values are shown with “or”, the hazard statement is shared by more than one category or by more than one class, and the code alone does not say which. H272, for example, belongs to oxidising liquids and to oxidising solids — the physical state decides. The binding answer for a specific entry is in the CLP Annex VI table itself.

Hexachlorocyclopentadiene hazard statements (H-codes)

Hazard statements assigned to Hexachlorocyclopentadiene
CodeHazard statement
H330 Fatal if inhaled.
H311 Toxic in contact with skin.
H302 Harmful if swallowed.
H314 Causes severe skin burns and eye damage.
H400 Very toxic to aquatic life.
H410 Very toxic to aquatic life with long lasting effects.

This page lists only the codes assigned to Hexachlorocyclopentadiene. 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 Hexachlorocyclopentadiene

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 Hexachlorocyclopentadi… 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

Hexachlorocyclopentadiene precautionary statements

CLP Annex VI assigns 15 precautionary statements to Hexachlorocyclopentadiene. 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.

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

Hexachlorocyclopentadiene 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 хексахлороциклопентадиен
Spanish español Hexaclorociclopentadieno
Czech čeština hexachlorcyklopenta-1,3-dien
Danish dansk hexachlorcyclopentadien
German Deutsch Hexachlorcyclopentadien
Estonian eesti heksaklorotsüklopentadieen
Greek ελληνικά εξαχλωροκυκλοπενταδιένιο
English English hexachlorocyclopentadiene
French français hexachlorocyclopentadiène
Croatian hrvatski heksaklorciklopentadien
Italian italiano esaclorociclopentadiene
Latvian latviešu heksahlorciklopentadiēns
Lithuanian lietuvių heksachlorciklopentadienas
Hungarian magyar hexaklórciklopentadién
Maltese Malti eżakloroċiklopentadjen
Dutch Nederlands hexachloorcyclopentadieen
Polish polski heksachlorocyklopentadien
Portuguese português hexaclorociclopentadieno
Romanian română hexaclorociclopentadienă
Slovak slovenčina hexachlórcyklopentadién
Slovenian slovenščina heksaklorociklopentadien
Finnish suomi heksakloorisyklopentadieeni
Swedish svenska hexaklorcyklopentadien

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

Hexachlorocyclopentadiene GHS label elements

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

GHS06 Skull and crossbones pictogramGHS05 Corrosion pictogramGHS09 Environment pictogram

Danger

Hexachlorocyclopentadiene

  • Fatal if inhaled.
  • Toxic in contact with skin.
  • Harmful if swallowed.
  • Causes severe skin burns and eye damage.
  • Very toxic to aquatic life.
  • Very toxic to aquatic life with long lasting effects.
  • Do not breathe dust/fume/gas/mist/vapours/spray.
  • Do not eat, drink or smoke when using this product.
  • Use only outdoors or in a well-ventilated area.
  • Avoid release to the environment.
  • Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/
  • IF SWALLOWED:
  • IF ON SKIN:
  • IF INHALED:
  • Immediately call a POISON CENTER/doctor/
  • Call a POISON CENTER/doctor/ if you feel unwell.
  • Rinse mouth.
  • Do NOT induce vomiting.
  • Wash with plenty of water/
  • Collect spillage.
  • Dispose of contents/container to

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

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

07 · Health hazards

Hexachlorocyclopentadiene health hazards and exposure limits

Hexachlorocyclopentadiene hazard summary

HCCPD is a manufactured chemical that does not occur naturally. It is a light, lemon-yellow liquid that has a sharp musty odor. It easily evaporates into the air; the vapor looks like a blue haze. HCCPD is used in the manufacture of certain pesticides. Most of the HCCPD in the environment results from releases during its production and disposal. It is also used to make flame retardants, resins that won't burn, shock-proof plastics, esters, ketones, fluorocarbons, and dyes.

Source: Agency for Toxic Substances and Disease Registry (ATSDR)

Hexachlorocyclopentadiene carcinogenicity classification

Under the conditions of these 2-year studies, there was no evidence of carcinogenic activity of hexachlorocyclopentadiene in male or female F344/N rats or B6C3F1 mice exposed to 0.01, 0.05, or 0.2 ppm.

Source: US National Toxicology Program · TR-437: Toxicology and Carcinogenesis Studies of Hexachlorocyclopentadiene (CASRN 77-47-4) in F344/N Rats and B6C3F1 Mice (Inhalation Studies) (1994 )

Cancer Classification: Group D Not Classifiable as to Human Carcinogenicity

Source: Hazardous Substances Data Bank (HSDB)

CLASSIFICATION: D; not classifiable as to human carcinogenicity. BASIS FOR CLASSIFICATION: Inadequate data in humans and no data in animals concerning carcinogenicity of hexachlorocyclopentadiene. HUMAN CARCINOGENICITY DATA: Inadequate.

Source: Hazardous Substances Data Bank (HSDB)

An IARC group and a CLP classification answer different questions. IARC judges whether the evidence for cancer in humans is strong enough; CLP Annex VI is the legally binding EU classification. A substance can carry one and not the other.

Hexachlorocyclopentadiene occupational exposure limits

US occupational exposure limits reported for Hexachlorocyclopentadiene. PEL is enforceable (OSHA), REL is a recommendation (NIOSH), IDLH is the concentration at which escape becomes impossible without injury.
Limit Value Source
PEL none See Appendix G The National Institute for Occupational Safety and Health (NIOSH)
REL 0.01 ppm (0.1 mg/m³) Occupational Safety and Health Administration (OSHA)
REL TWA 0.01 ppm (0.1 mg/m3) The National Institute for Occupational Safety and Health (NIOSH)
IDLH N.D. The National Institute for Occupational Safety and Health (NIOSH)

These are United States values. The European Union sets its own indicative and binding limits, and the figure that applies at a given workplace is the one in the local regulation — not the one shown here.

08 · Physical and chemical properties

Hexachlorocyclopentadiene 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.

Hexachlorocyclopentadiene boiling point

Property Value Conditions Source
Boiling point 239 °C (462.2 °F) HSDB
238.89 °C (462 °F) NIOSH
238.89 °C (462 °F) at 753 mmHg CAMEO

Hexachlorocyclopentadiene melting point

Property Value Conditions Source
Melting point -9 °C (15.8 °F) HSDB
-8.89 °C (16 °F) NIOSH

Hexachlorocyclopentadiene density

Property Value Conditions Source
Density 1.71 g/cm³ NIOSH
1.7019 g/cm³ at 25 °C HSDB

Hexachlorocyclopentadiene solubility

Property Value Conditions Source
Solubility Soluble in all proportions in acetone, carbon tetrachloride, methanol and hexane. HSDB
In water, 1.8 mg/L at 25 °C at 25 °C HSDB
(77 °F): 0.0002% (Reacts) at 25 °C NIOSH

Hexachlorocyclopentadiene vapor pressure

Property Value Conditions Source
Vapor pressure 0.06 mmHg at 25 °C, Extrapolated HSDB
0.08 mmHg at 25 °C NIOSH

Hexachlorocyclopentadiene flash point

Property Value Conditions Source
Flash point Non-flammable (EPA, 1998) CAMEO

Hexachlorocyclopentadiene lower explosive limit (LEL)

Property Value Conditions Source
Lower explosive limit (LEL) In presence of moisture explosive hydrogen gas may collect in enclosed space. HSDB
Noncombustible Liquid NIOSH

Hexachlorocyclopentadiene vapor density

Property Value Conditions Source
Vapor density 9.4 (air = 1) HSDB

Hexachlorocyclopentadiene odor threshold

Property Value Conditions Source
Odor threshold 0.15 ppm or 1.7 mg/cu m HSDB
Odor low: 1.5 mg/cu m; Odor high: 3.3 mg/cu m HSDB
Odor Threshold Low: 0.15 [ppm] Haz-Map

Hexachlorocyclopentadiene corrosivity

Property Value Conditions Source
Corrosivity In presence of moisture, will corrode iron & other metals. HSDB

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

09 · Fire and explosion

Hexachlorocyclopentadiene fire and explosion behaviour

These are descriptions rather than measured values, so they are kept out of the table above and quoted here with the source that reported them.

Hexachlorocyclopentadiene fire potential

Nonflammable

Source: Hazardous Substances Data Bank (HSDB)

10 · Handling and storage

Hexachlorocyclopentadiene storage and handling

Hexachlorocyclopentadiene safe storage

Store in an area without drain or sewer access. Dry. Well closed. Ventilation along the floor.

Source: ILO-WHO International Chemical Safety Cards (ICSCs)

Hexachlorocyclopentadiene incompatible materials

Reacts slowly with water to form hydrochloric acid.

Source: Hazardous Substances Data Bank (HSDB)

Hexachlorocyclopentadiene reactivity

HEXACHLOROCYCLOPENTADIENE is incompatible with strong oxidizing and reducing agents. Also incompatible with many amines, nitrides, azo/diazo compounds, alkali metals (sodium), and epoxides.

Source: CAMEO Chemicals

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

11 · Questions

Hexachlorocyclopentadiene — frequently asked questions

What is the CAS number of Hexachlorocyclopentadiene?

The CAS number of Hexachlorocyclopentadiene is 77-47-4. Its EC number is 201-029-3.

What is the chemical formula of Hexachlorocyclopentadiene?

The molecular formula of Hexachlorocyclopentadiene is C5Cl6 and its molecular weight is 272.8 g/mol.

What does a Hexachlorocyclopentadiene label have to show?

Under CLP Annex VI the label for Hexachlorocyclopentadiene carries the pictograms Skull and crossbones, Corrosion and Environment and the signal word is Danger.

Is Hexachlorocyclopentadiene flammable?

CLP Annex VI assigns Hexachlorocyclopentadiene 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 Non-flammable (EPA, 1998) (CAMEO).

Is Hexachlorocyclopentadiene a carcinogen?

CLP Annex VI records no harmonised carcinogenicity classification for Hexachlorocyclopentadiene. 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 exposure limit for Hexachlorocyclopentadiene?

The US occupational exposure limit reported for Hexachlorocyclopentadiene is none See Appendix G (The National Institute for Occupational Safety and Health (NIOSH)). Limits differ by country: the EU sets its own indicative and binding values, and the figure that applies at a given workplace is the one in the local regulation.

What is the boiling point of Hexachlorocyclopentadiene?

The boiling point reported for Hexachlorocyclopentadiene is 239 °C (462.2 °F) (HSDB).

What is the melting point of Hexachlorocyclopentadiene?

The melting point reported for Hexachlorocyclopentadiene is -9 °C (15.8 °F) (HSDB).

Nearby

Substances next to Hexachlorocyclopentadiene

Keep going: substances starting with H, or search the whole database by name, CAS number, pictogram or signal word.

Get the free GHS / CLP / OSHA deadline calendar

Verified 2026–2029 compliance dates in one PDF — plus alerts when the rules change.