Substance profile
Symclosene
Symclosene is needles from ethylene chloride with a chlorine odor.
01 · Identification
What Symclosene is
Symclosene is needles from ethylene chloride with a chlorine odor. Its molecular formula is C3Cl3N3O3 and its molecular weight is 232.41 g/mol. It melts at 235 °C, is soluble in water.
Under the GHS it carries the signal word Danger. It is classed as reactive agents - 2nd degree.
02 · Identifiers
Symclosene identifiers and molecular data
Symclosene CAS number and EC number
Symclosene molecular formula and molecular weight
Other names for Symclosene
- trichloroisocyanuric acid
- trichloro-1,3,5-triazinetrion
03 · GHS classification
Symclosene hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Symclosene pictograms and signal word
Symclosene hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Oxidising liquids or Oxidising solids | Category 2 or 3 | H272 | GHS03 |
| Acute toxicity - oral GHS chapter 3.1 | Category 4 | H302 | GHS07 |
| Serious eye damage/eye irritation GHS chapter 3.3 | Category 2A | H319 | GHS07 |
| Specific target organ toxicity - single exposure GHS chapter 3.8 | Category 3 | H335 | GHS07 |
| 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.
Symclosene hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H272 | May intensify fire; oxidiser. |
| H302 | Harmful if swallowed. |
| H335 | May cause respiratory irritation. |
| H319 | Causes serious eye irritation. |
| H400 | Very toxic to aquatic life. |
| H410 | Very toxic to aquatic life with long lasting effects. |
Symclosene supplemental EU statements (EUH)
| Code | Statement |
|---|---|
| EUH031 | Contact with acids liberates toxic gas. |
This page lists only the codes assigned to Symclosene. 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 Symclosene
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 Symclosene 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
Symclosene precautionary statements
CLP Annex VI assigns 13 precautionary statements to Symclosene. 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
Symclosene 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 | симклозен трихлороизоцианурова киселинатрихлоро-1,3,5-триазинтрион |
| Spanish español | Simcloseno ácido tricloroisocianúricotricloro-1,3,5-triazinatriona |
| Czech čeština | symklosen trichlorisokyanurová kyselina1,3,5-trichlor-1,3,5-triazin-2(1 H ),4(3 H ),6(5 H )-trion |
| Danish dansk | symclosen trichlorisocyanursyretrichlor-1,3,5-triazinetrion |
| German Deutsch | Symclosen TrichlorisocyanursäureTrichlor-1,3,5-triazintrion |
| Estonian eesti | sümkloseen trikloroisotsüanuurhapetrikloro-1,3,5-triasiintrioon |
| Greek ελληνικά | συμκλοσένιο τριχλωροϊσοκυανουρικό οξύτριχλωρο-1,3,5-τριαζινετριόνη |
| English English | symclosene trichloroisocyanuric acidtrichloro-1,3,5-triazinetrion |
| French français | symclosène acide trichloroisocyanuriquetrichloro-1,3,5-triazinetrion |
| Croatian hrvatski | simklozen triklorizocijanurska kiselinatriklor-1,3,5-triazintrion |
| Italian italiano | simclosene acido tricloroisocianuricotricloro-1,3,5-triazintrione |
| Latvian latviešu | simklozēns trihlorizocianūrskābetrihlor-1,3,5-triazīntrions |
| Lithuanian lietuvių | simklosenas trichlorizocianuro rūgštistrichlor-1,3,5-triazintrionas |
| Hungarian magyar | szimklozén triklórizocianursavtriklór-1,3,5-triazintrion |
| Maltese Malti | symclosene aċidu dikloroisoċjanurikutrikloro-1,3,5-triażinatrion |
| Dutch Nederlands | symcloseen trichloorisocyanuurzuurtrichloor-1,3,5-triazinetrion |
| Polish polski | symklozen kwas trichloroizocyjanurowy1,3,5-trichloro-1,3,5-triazinano-2,4,6-trion |
| Portuguese português | sinclosena ácido tricloroisocianúricotricloro-1,3,5-triazinatriona |
| Romanian română | simclosen acid tricloroizocianurictricloro-1,3,5-triazintrionă |
| Slovak slovenčina | symklozén kyselina trichlórizokyanurová1,3,5-trichlór-1,3,5-triazín-2(1 H ),4(3 H ),6(5 H )-trión |
| Slovenian slovenščina | simklozen trikloroizocianurska kislinatrikloro-1,3,5-triazintrion |
| Finnish suomi | symkloseeni trikloori-isosyanuurihappotrikloori-1,3,5-triatsiinitrioni |
| Swedish svenska | symklosen triklorisocyanursyratriklor-1,3,5-triazintrion |
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
Symclosene GHS label elements
Everything CLP Annex VI fixes for Symclosene, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Symclosene
- May intensify fire; oxidiser.
- Harmful if swallowed.
- May cause respiratory irritation.
- Causes serious eye irritation.
- Very toxic to aquatic life.
- Very toxic to aquatic life with long lasting effects.
- Contact with acids liberates toxic gas.
- Wash … thoroughly after handling.
- Do not eat, drink or smoke when using this product.
- Avoid release to the environment.
- Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/…
- IF SWALLOWED:
- IF IN EYES:
- Call a POISON CENTER/doctor/… if you feel unwell.
- Get medical advice/attention.
- Rinse mouth.
- If eye irritation persists:
- Remove contact lenses, if present and easy to do. Continue rinsing.
- Collect spillage.
- Dispose of contents/container to …
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Symclosene in the GHS label constructor →
07 · Physical and chemical properties
Symclosene 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.
Symclosene melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | 235 °C (455 °F) | DOE PAC | |
| 246.7 °C (476.1 °F) | decomposes, decomposes | HSDB |
Symclosene density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 2.07 g/cm³ | ICSC | |
| 1 g/cm³ | DOE PAC | ||
| 1 g/cm³ | at 20 °C, est | CAMEO |
Symclosene solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Soluble in chlorinated and highly polar solvents | HSDB | |
| Solubility in water at 25 °C = 1 g/100 g; Solubility in acetone at 30 °C = 35.0 g/100 g | at 25 °C | HSDB | |
| Water solubility = 1.2% = 1.20X10+4 mg/L at 25 °C | at 25 °C | HSDB |
Symclosene vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 1.2e-7 mmHg | Haz-Map | |
| negligible | ICSC |
Symclosene flash point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Flash point | 250 °C (482 °F) | above this value | HSDB |
Symclosene lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | Closed containers may rupture violently when heated. | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
08 · Fire and explosion
Symclosene 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.
Symclosene fire potential
Noncombustible, but due to high reactivity (chlorination, oxidation), may cause ignition by contact with many substances, organic substances easily chlorinated or oxidizeD.
Source: Hazardous Substances Data Bank (HSDB)
Fire and explosion
Calcium hypochlorite and trichloro-s-triazinetrione were tested in a bomb apparatus measuring temperature and gas production. Combining the two chlorinators at 2, 6, 12, or 18 g of each produced a progressive increase in gas production from 234 to 1422 mL. The temperature increased from 30 degrees C at 2 g to 63 degrees C at 18 g. The time to complete the reaction decreased from 6.2 minutes at 2 g to 3.8 minutes at 18 g. The third run at the 18 g level resulted in an explosion. The results indicate that gas generation is dependent on both products.
Source: HSDB
09 · Handling and storage
Symclosene storage and handling
Symclosene safe storage
Dry. Well closed. Separated from amines, combustible substances and reducing agents. See Chemical Dangers. Store in an area without drain or sewer access. Provision to contain effluent from fire extinguishing.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Symclosene storage conditions
Store in a cool, dry, well-ventilated location. Outside or detached storage is preferred. Must be stored in a dry location on pallets arranged according to NFPA 430, Code for Storage of Liquids and Solid Oxidizers. Separate from combustibles, oxidizables, ammonia, sodium carbonate (soda ash), calcium hypochlorite, hydrogen peroxide.
Source: Hazardous Substances Data Bank (HSDB)
Symclosene incompatible materials
A powerful oxidizer. Violent reaction with reducing agents, combustible materials.
Source: Hazardous Substances Data Bank (HSDB)
Symclosene reactivity
TRICHLORO-S-TRIAZINETRIONE, DRY is an oxidizer. It reacts with combustible materials or ammonium salts, resulting in fire. It is thermally unstable, and reacts with small amounts of water to release toxic chlorine gas and explosive nitrogen trichloride. Reaction of this compound with ammonia or amines also produces nitrogen trichloride. This compound reacts explosively with calcium hypochlorite and water. [NFPA 49, 14th ed. 2010]
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Symclosene in the storage compatibility matrix →
10 · Transport
Symclosene UN number and transport classification
Transport classification is a separate system from the GHS classification above. It decides how a package is marked and how a load may be carried; it does not follow from the workplace label, and the workplace label does not follow from it. The entries below are linked by CAS number, never by name.
Symclosene under UN 2468 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| TRICHLOROISOCYANURIC ACID, DRY | 5.1 | O2 | II | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 5.1 is “Oxidizing substances” (ADR 2.1.1.1).
United States · 49 CFR 172.101 Hazardous Materials Table
| Proper shipping name (column 2) | Class or division | PG | Labels (column 6) |
|---|---|---|---|
| Trichloroisocyanuric acid, dry | 5.1 | II | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 5.1 is “Oxidizer” (49 CFR 173.2).
11 · Questions
Symclosene — frequently asked questions
What is the CAS number of Symclosene?
The CAS number of Symclosene is 87-90-1. Its EC number is 201-782-8.
What is the chemical formula of Symclosene?
The molecular formula of Symclosene is C3Cl3N3O3 and its molecular weight is 232.41 g/mol.
What does a Symclosene label have to show?
Under CLP Annex VI the label for Symclosene carries the pictograms Flame over circle, Exclamation mark and Environment and the signal word is Danger.
Is Symclosene flammable?
CLP Annex VI assigns Symclosene 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 250 °C (482 °F), above this value (HSDB).
Is Symclosene a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Symclosene. 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 melting point of Symclosene?
The melting point reported for Symclosene is 235 °C (455 °F) (DOE PAC).
How should Symclosene be stored?
Store in a cool, dry, well-ventilated location. Outside or detached storage is preferred. Must be stored in a dry location on pallets arranged according to NFPA 430, Code for Storage of Liquids and Solid Oxidizers. Separate from combustibles, oxidizables, ammonia, sodium carbonate (soda ash), calcium hypochlorite, hydrogen peroxide. (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Symclosene
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