Substance profile
Thionyl Chloride
Thionyl Chloride is a colorless to pale yellow or reddish liquid with a suffocating odor.
01 · Identification
What Thionyl Chloride is
Thionyl Chloride is a colorless to pale yellow or reddish liquid with a suffocating odor. Its molecular formula is Cl2OS and its molecular weight is 118.97 g/mol. It boils at 76 °C, melts at -104 °C.
Under the GHS it carries the signal word Danger. It is classed as corrosives.
02 · Identifiers
Thionyl Chloride identifiers and molecular data
Thionyl Chloride CAS number and EC number
Thionyl Chloride molecular formula and molecular weight
Other names for Thionyl Chloride
- thionyl dichloride
03 · GHS classification
Thionyl Chloride hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Thionyl Chloride pictograms and signal word
Thionyl Chloride hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Acute toxicity - oral GHS chapter 3.1 | Category 4 | H302 | GHS07 |
| Acute toxicity - inhalation GHS chapter 3.1 | Category 4 | H332 | GHS07 |
| Skin corrosion/irritation GHS chapter 3.2 | Category 1A or 1B or 1C | H314 | GHS05 |
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.
Thionyl Chloride hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H332 | Harmful if inhaled. |
| H302 | Harmful if swallowed. |
| H314 | Causes severe skin burns and eye damage. |
Thionyl Chloride supplemental EU statements (EUH)
| Code | Statement |
|---|---|
| EUH014 | Reacts violently with water. |
| EUH029 | Contact with water liberates toxic gas. |
This page lists only the codes assigned to Thionyl Chloride. 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 Thionyl Chloride
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 Thionyl Chloride 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
Thionyl Chloride precautionary statements
CLP Annex VI assigns 10 precautionary statements to Thionyl Chloride. 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.
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
Thionyl Chloride 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 | тионилдихлорид тионилхлорид |
| Spanish español | Dicloruro de tionilo cloruro de tionilo |
| Czech čeština | thionyl-chlorid chlorid thionylu |
| Danish dansk | thionyldichlorid thionylchlorid |
| German Deutsch | Thionyldichlorid Thionylchlorid |
| Estonian eesti | tionüüldikloriid tionüülkloriid |
| Greek ελληνικά | θειονυλοδιχλωρίδιο θειονυλοχλωρίδιο |
| English English | thionyl dichloride thionyl chloride |
| French français | dichlorure de thionyle chlorure de thionyle |
| Croatian hrvatski | tionil-diklorid tionil-klorid |
| Italian italiano | dicloruro di tionile cloruro di tionile |
| Latvian latviešu | tionildihlorīds tionilhlorīds |
| Lithuanian lietuvių | tionildichloridas tionilchloridas |
| Hungarian magyar | tionil-diklorid tionil-klorid |
| Maltese Malti | diklorur tat-tijonil klorur tat-tijonil |
| Dutch Nederlands | thionyldichloride thionylchloride |
| Polish polski | dichlorek sulfinylu dichlorek tionyluchlorek tionyludichlorek tlenek siarkitlenochlorek siarki |
| Portuguese português | dicloreto de tionilo cloreto de tionilo |
| Romanian română | diclorură de tionil clorură de tionil |
| Slovak slovenčina | dichlorid-oxid siričitý chlorid tionylu |
| Slovenian slovenščina | tionil diklorid tionil klorid |
| Finnish suomi | tionyylidikloridi tionyylikloridi |
| Swedish svenska | tionyldiklorid tionylklorid |
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
Thionyl Chloride GHS label elements
Everything CLP Annex VI fixes for Thionyl Chloride, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Thionyl Chloride
- Harmful if inhaled.
- Harmful if swallowed.
- Causes severe skin burns and eye damage.
- Reacts violently with water.
- Contact with water liberates toxic gas.
- 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.
- Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/…
- IF SWALLOWED:
- IF INHALED:
- Immediately call a POISON CENTER/doctor/…
- Call a POISON CENTER/doctor/… if you feel unwell.
- Rinse mouth.
- Do NOT induce vomiting.
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Thionyl Chloride in the GHS label constructor →
07 · Health hazards
Thionyl Chloride health hazards and exposure limits
Thionyl Chloride hazard summary
Can cause pneumonitis; [ACGIH] Toxicity is comparable to hydrogen chloride; liquid may cause severe skin burns; [HSDB] Corrosive to skin; [Quick CPC] A lachrymator; [HSDB] A corrosive substance that can cause pulmonary edema; [ICSC] Sulfur chlorides release HCl, SO2, and H2S when spilled in water; [ERG 2016] Thionyl chloride is fibrogenic to the lungs in the context of an acute inhalation exposure complicated by bronchiolitis obliterans.
Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
Thionyl Chloride occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | none See Appendix G | The National Institute for Occupational Safety and Health (NIOSH) |
| REL | 1 ppm (5 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| REL | C 1 ppm (5 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
Thionyl Chloride 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.
Thionyl Chloride boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 76 °C (168.8 °F) | at 760 mmHg | HSDB |
| 76.11 °C (169 °F) | NIOSH | ||
| 76.11 °C (169 °F) | at 760 mmHg | CAMEO |
Thionyl Chloride melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | -104.5 °C (-156.1 °F) | HSDB | |
| -104.44 °C (-156 °F) | NIOSH |
Thionyl Chloride density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 1.64 g/cm³ | NIOSH |
Thionyl Chloride solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Decomp in acids, alc, alkalies; in cold and hot water | HSDB | |
| Miscible with benzene, chloroform, carbon tetrachloride | HSDB | ||
| Decomposes (fumes) in water | decomposes | HSDB |
Thionyl Chloride vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 100 mmHg | at 21.11 °C | NIOSH |
| 110 mmHg | at 26 °C | HSDB |
Thionyl Chloride lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | Noncombustible Liquid | NIOSH |
Thionyl Chloride vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 4.1 (air = 1) | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Thionyl Chloride 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.
Thionyl Chloride fire potential
This chemical is a noncombustible liquid.
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
Thionyl Chloride storage and handling
Thionyl Chloride safe storage
Ventilation along the floor. Separated from food and feedstuffs. See Chemical Dangers. Dry. Well closed.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Thionyl Chloride 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. Keep away from water. Never allow product to get in contact with water during storage. Handle and store under inert gas. Storage class (TRGS 510): 6.1D: Non-combustible, acute toxic Cat.3 / toxic hazardous materials or hazardous materials causing chronic effects.
Source: Hazardous Substances Data Bank (HSDB)
Thionyl Chloride incompatible materials
Incompatible materials: Alcohols, amines, metals, reacts violently with water.
Source: Hazardous Substances Data Bank (HSDB)
Planning storage for a mix of chemicals? Check Thionyl Chloride in the storage compatibility matrix →
11 · Transport
Thionyl Chloride 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.
Thionyl Chloride under UN 1836 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| THIONYL CHLORIDE | 8 | C1 | I | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 8 is “Corrosive 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) |
|---|---|---|---|
| Thionyl chloride | 8 | I | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 8 is “Corrosive material” (49 CFR 173.2).
12 · Questions
Thionyl Chloride — frequently asked questions
What is the CAS number of Thionyl Chloride?
The CAS number of Thionyl Chloride is 7719-09-7. Its EC number is 231-748-8.
What is the chemical formula of Thionyl Chloride?
The molecular formula of Thionyl Chloride is Cl2OS and its molecular weight is 118.97 g/mol.
What does a Thionyl Chloride label have to show?
Under CLP Annex VI the label for Thionyl Chloride carries the pictograms Corrosion and Exclamation mark and the signal word is Danger.
Is Thionyl Chloride flammable?
CLP Annex VI assigns Thionyl Chloride 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.
Is Thionyl Chloride a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Thionyl Chloride. 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 Thionyl Chloride?
The US occupational exposure limit reported for Thionyl Chloride 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 Thionyl Chloride?
The boiling point reported for Thionyl Chloride is 76 °C (168.8 °F), at 760 mmHg (HSDB).
What is the melting point of Thionyl Chloride?
The melting point reported for Thionyl Chloride is -104.5 °C (-156.1 °F) (HSDB).
How should Thionyl Chloride 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. Keep away from water. Never allow product to get in contact with water during storage. Handle and store under inert gas. Storage class (TRGS 510): 6.1D: Non-combustible, acute toxic Cat.3 / toxic hazardous materials or hazardous materials causing chronic effects. (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Thionyl Chloride
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