| Name | Sulfuryl fluoride |
| Formula | SO₂F₂ |
| IUPAC name | sulfuryl difluoride |
| CAS number | 2699-79-8 |
| EC number | 220-281-5 |
| UN number | 2191 — Sulphuryl fluoride |
| Transport class (ADR/RID) | 2.3 (Toxic gases) |
| PubChem CID | 17607 |
| Synonyms | Sulfur difluoride dioxide, Vikane® |
| Molar mass | 102.06 g/mol |
| Boiling point (1 atm) | -55.4 °C |
| Melting point | -135.8 °C |
| Critical temperature | 91.8 °C |
| Critical pressure | — |
| Vapour pressure | 17 bar at 21.1 °C |
| Gas density | 4.6261 kg/m³ (0 °C, 1013 mbar) |
| Relative density (air = 1) | 3.47 |
| Solubility in water | Concentration: 2 g/l |
| Appearance | gas liquefied under pressure, colourless, odourless |
| Odour | odourless |
| 1 ppm at 20 °C | 4.24 mg/m³ |
Boiling point -55.4 °C at 1 atm: a liquefied gas under its own vapour pressure in cylinders. Critical point 91.8 °C: below this temperature it can be stored as a liquid; cylinder pressure then equals the vapour pressure. Vapour pressure ≈ 17 bar at 21.1 °C — this is the pressure inside a cylinder or a switchgear compartment at that temperature, and it rises steeply with temperature (Clausius–Clapeyron). Relative density 3.47 (air = 1): heavier than air — accumulates in pits, cable basements and at floor level; place sensors low. Conversion at 20 °C, 1013 mbar: 1 ppm = 4.24 mg/m³; NDIR reads partial pressure, so readings scale with absolute pressure (value = reading × P/1013) and must be pressure-compensated.
| Hazard class | toxic (fumigant; delayed CNS/respiratory effects) |
| GHS signal word | Danger |
| CLP classification | Gases under pressure, liquefied gas; H280 Acute toxicity, Category 3, inhalation; H331 Specific Target Organ Toxicity (repeated exposure), Category 2; H373 Hazardous to the aquatic environment, Acute Category 1; H400 |
| Hazard statements | H280: Contains gas under pressure; may explode if heated. H331: Toxic if inhaled. H373: May cause damage to organs through prolonged or repeated exposure. H400: Very toxic to aquatic life. |
| Lower / upper explosion limit | non-flammable |
| Auto-ignition temperature | — |
| Seveso III named substance | yes |
| EU indicative OELV (8 h TWA) | no EU IOELV |
| EU IOELV short-term (15 min) | — |
| Germany AGW (TRGS 900) | — |
| Netherlands | wettelijke grenswaarde per Arboregeling bijlage XIII — SER grenswaarden database |
| NIOSH REL (USA) | TWA 5 ppm (20 mg/m3) ST 10 ppm (40 mg/m3) |
| OSHA PEL (USA) | TWA 5 ppm (20 mg/m3) See Appendix G |
| IDLH | 200 ppm |
Fumigant with no odour warning. Acute exposure irritates lungs (delayed pulmonary oedema); high doses cause CNS effects — nausea, seizures, coma. Chronic exposure risk to kidneys. NIOSH REL 5 ppm TWA, IDLH 200 ppm.
- NDIR (≈7.2/8.8 µm) is the method of choice for fumigation clearance and structural fumigation monitoring; PID cannot see it; EC cells are not selective.
- Limits: 5 ppm 8-h TWA (NIOSH/OSHA), 10 ppm STEL; re-entry clearance typically ≤1 ppm.
| GWP₁₀₀ — IPCC AR6 | 4630 |
| GWP₁₀₀ — IPCC AR4 | — |
| GWP used in Reg. (EU) 2024/573 | not listed |
| Atmospheric lifetime | 36 years |
| Ozone depletion potential | 0 |
| Main IR absorption band (NDIR) | 7.2 µm (S=O stretch, ≈1390 cm⁻¹); 8.8 µm; 11.4 µm (S–F) |
| Note | Not an F-gas under 2024/573 despite high GWP; it is a fumigant regulated under biocides/plant-protection law. |
- Biocidal Products Regulation 528/2012 / fumigation permits — clearance measurement before re-entry
- Workplace: NIOSH/OSHA 5 ppm TWA, 10 ppm STEL; GWP 4630 (AR6)
Tell us what you measure — just tap
Three taps and an email. An engineer replies within 24 h with feasibility and a price indication.
- https://gestis-database.dguv.de/data?name=500105
- https://www.cdc.gov/niosh/npg/npgd0581.html
- https://pubchem.ncbi.nlm.nih.gov/compound/17607
- IPCC AR6 WG1 Ch.7 Supplementary Material, Table 7.SM.7 (https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter07_SM.pdf)
- HITRAN/NIST IR band positions (approximate centre of the strongest band used for NDIR; https://hitran.org, https://webbook.nist.gov)
- PubChem CID 17607 (ICSC: 1700 kPa at 21.1 °C); critical pressure not verified — left null