Substance profile
Oxalonitrile
Oxalonitrile is a colorless gas; burns with purple tinged flame with an almond-like odor, which is acrid and pungent in lethal concentrations.
01 · Identification
What Oxalonitrile is
Oxalonitrile is a colorless gas; burns with purple tinged flame with an almond-like odor, which is acrid and pungent in lethal concentrations. It boils at -21.1 °C, melts at -27.8 °C, is soluble in water.
Under the GHS it carries the signal word Danger. It is classed as flammable agents - 4th degree.
02 · Identifiers
Oxalonitrile identifiers and molecular data
Oxalonitrile CAS number and EC number
Oxalonitrile molecular formula and molecular weight
Other names for Oxalonitrile
- cyanogen
03 · GHS classification
Oxalonitrile hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Oxalonitrile pictograms and signal word
Oxalonitrile hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Flammable gases GHS chapter 2.2 | Category 1A | H220 | GHS02 |
| Acute toxicity - inhalation GHS chapter 3.1 | Category 3 | H331 | GHS06 |
| 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 |
Oxalonitrile hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H220 | Extremely flammable gas. |
| H331 | Toxic if inhaled. |
| H400 | Very toxic to aquatic life. |
| H410 | Very toxic to aquatic life with long lasting effects. |
This page lists only the codes assigned to Oxalonitrile. 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 Oxalonitrile
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 Oxalonitrile 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
Oxalonitrile precautionary statements
CLP Annex VI assigns 10 precautionary statements to Oxalonitrile. 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
Oxalonitrile 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 | оксалонитрил цианоген |
| Spanish español | Oxalonitrilo cianógeno |
| Czech čeština | oxalonitril dinitril šťavelové kyseliny |
| Danish dansk | oxalonitril cyanogen |
| German Deutsch | Dicyan OxalyldinitrilCyanogen |
| Estonian eesti | oksalonitriil tsüanogeen |
| Greek ελληνικά | οξαλονιτρίλιο κυάνιοκυανογόνοδικυάνιο |
| English English | oxalonitrile cyanogen |
| French français | oxalonitrile cyanogène |
| Croatian hrvatski | oksalonitril cijanogen |
| Italian italiano | ossalonitrile cianogeno |
| Latvian latviešu | skābeņskābes ciāndinitrils diciāns |
| Lithuanian lietuvių | oksalonitrilas cianogenas |
| Hungarian magyar | oxalonitril cianogén |
| Maltese Malti | ossalonitril ċjanoġen |
| Dutch Nederlands | oxalonitril cyanogeen |
| Polish polski | etanodinitryl cyjanogendicyjandinitryl kwasu szczawiowego |
| Portuguese português | oxalonitrilo cianogénio |
| Romanian română | oxalonitril cianogen |
| Slovak slovenčina | oxalonitril |
| Slovenian slovenščina | oksalonitril cianogen |
| Finnish suomi | oksalonitriili syanogeeni |
| Swedish svenska | oxalonitril cyanogen |
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
Oxalonitrile GHS label elements
Everything CLP Annex VI fixes for Oxalonitrile, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Oxalonitrile
- Extremely flammable gas.
- Toxic if inhaled.
- Very toxic to aquatic life.
- Very toxic to aquatic life with long lasting effects.
- Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
- Keep container tightly closed.
- Do not breathe dust/fume/gas/mist/vapours/spray.
- Use only outdoors or in a well-ventilated area.
- Avoid release to the environment.
- IF INHALED:
- Immediately call a POISON CENTER/doctor/…
- Collect spillage.
- Store in a well-ventilated place.
- Dispose of contents/container to …
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Oxalonitrile in the GHS label constructor →
07 · Health hazards
Oxalonitrile health hazards and exposure limits
Oxalonitrile occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | 10 ppm (Construction and Maritime industries only) | Occupational Safety and Health Administration (OSHA) |
| PEL | none See Appendix G | The National Institute for Occupational Safety and Health (NIOSH) |
| REL | 10 ppm (20 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| REL | TWA 10 ppm (20 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
Oxalonitrile 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.
Oxalonitrile boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | -21.1 °C (-6 °F) | HSDB | |
| -21.11 °C (-6 °F) | NIOSH | ||
| -21.17 °C (-6.1 °F) | at 760 mmHg | CAMEO |
Oxalonitrile melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | -27.83 °C (-18.1 °F) | HSDB | |
| -27.9 °C (-18.2 °F) | HSDB | ||
| -27.78 °C (-18 °F) | NIOSH |
Oxalonitrile density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 0.9537 g/cm³ | at 21 °C | DOE PAC |
| 0.9537 g/cm³ | at -21 °C | HSDB | |
| 0.954 g/cm³ | at -21 °C | CAMEO |
Oxalonitrile solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Soluble in ethanol, ethyl ether | HSDB | |
| Solubility at 20 °C: water dissolves 4.5 times its own volume of cyanogen; diethyl ether, 5.0 times; and ethanol, 23.0 times | at 20 °C | HSDB | |
| 450 CC IN 100 ML WATER @ 20 °C | at 20 °C | HSDB |
Oxalonitrile vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 3876 mmHg | at 21.11 °C | NIOSH |
| 4300 mmHg | at 25 °C | HSDB |
Oxalonitrile flash point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Flash point | NA (Gas) | NIOSH | |
| Flammable gas | ICSC |
Oxalonitrile lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | 6.6 % by volume | HSDB | |
| 6 % by volume | HSDB |
Oxalonitrile upper explosive limit (UEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Upper explosive limit (UEL) | 32 % by volume | HSDB |
Oxalonitrile vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 1.8 (air = 1) | HSDB | |
| 1.82 (air = 1) | CAMEO |
Oxalonitrile odor threshold
| Property | Value | Conditions | Source |
|---|---|---|---|
| Odor threshold | Odor & irritation threshold detection tests on humans indicated no odor up to 250 ppm ... | HSDB | |
| Odor threshold is 500 mg/cu m; Irritation concentration is 32 mg/cu m. | HSDB | ||
| Odor threshold is >250 ppm | Haz-Map |
Oxalonitrile critical temperature and pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Critical temperature and pressure | 128.3 °C (262.9 °F) | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Oxalonitrile 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.
Oxalonitrile fire potential
Flammable gas.
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
Oxalonitrile storage and handling
Oxalonitrile safe storage
Fireproof. Cool.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Oxalonitrile storage conditions
Store in a cool, dry, well-ventilated location. Isolate from acids. Outside or detached storage is preferred.
Source: Hazardous Substances Data Bank (HSDB)
Oxalonitrile incompatible materials
Contact /with dichlorine oxide/ causes ignition or explosion.
Source: Hazardous Substances Data Bank (HSDB)
Oxalonitrile reactivity
Colorless, flammable, highly toxic gas. It can react explosively with strong oxidants (dichlorine oxide, fluorene, oxygen, ozone). When heated to decomposition or on contact with acids, acid fumes, water or steam it will react to produce deadly hydrogen cyanide gas and oxides of nitrogen [Sax, 9th ed., 1996, p. 945].
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Oxalonitrile in the storage compatibility matrix →
11 · Transport
Oxalonitrile 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.
Oxalonitrile under UN 1026 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| CYANOGEN | 2 | 2TF | — | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 2 is “Gases” (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) |
|---|---|---|---|
| Cyanogen | 2.3 | — | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 2.3 is “Poisonous gas” (49 CFR 173.2).
12 · Questions
Oxalonitrile — frequently asked questions
What is the CAS number of Oxalonitrile?
The CAS number of Oxalonitrile is 460-19-5. Its EC number is 207-306-5.
What does a Oxalonitrile label have to show?
Under CLP Annex VI the label for Oxalonitrile carries the pictograms Flame, Gas cylinder, Skull and crossbones and Environment and the signal word is Danger.
Is Oxalonitrile flammable?
Yes. CLP Annex VI assigns Oxalonitrile H220 — extremely flammable gas. The flash point reported for it is NA (Gas) (NIOSH).
Is Oxalonitrile a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Oxalonitrile. 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 Oxalonitrile?
The US occupational exposure limit reported for Oxalonitrile is 10 ppm (Construction and Maritime industries only) (Occupational Safety and Health Administration (OSHA)). 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 Oxalonitrile?
The boiling point reported for Oxalonitrile is -21.1 °C (-6 °F) (HSDB).
What is the melting point of Oxalonitrile?
The melting point reported for Oxalonitrile is -27.83 °C (-18.1 °F) (HSDB).
How should Oxalonitrile be stored?
CLP Annex VI assigns Oxalonitrile the storage statement P403. Store in a cool, dry, well-ventilated location. Isolate from acids. Outside or detached storage is preferred. (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Oxalonitrile
Keep going: substances starting with O, or search the whole database by name, CAS number, pictogram or signal word.