| Name | Heptafluoroisobutyronitrile (C4F7N, Novec 4710) |
| Formula | C₄F₇N |
| IUPAC name | 2,3,3,3-tetrafluoro-2-(trifluoromethyl)propanenitrile |
| CAS number | 42532-60-5 |
| EC number | 806-451-7 |
| UN number | 3163 — Liquefied gas, n.o.s. (heptafluoroisobutyronitrile) |
| Transport class (ADR/RID) | 2.2 (non-flammable, non-toxic gases) |
| PubChem CID | 12633773 |
| Synonyms | — |
| Molar mass | 195.04 g/mol |
| Boiling point (1 atm) | -4.7 °C |
| Melting point | -118 °C |
| Critical temperature | 112.9 °C |
| Critical pressure | 25 bar |
| Vapour pressure | 2.97 bar at 25 °C |
| Gas density | 7.9 kg/m³ (1 bar, ideal gas (3M)) |
| Relative density (air = 1) | 6.73 |
| Solubility in water | — |
| Appearance | colourless, non-flammable liquefied gas |
| Odour | not stated |
| 1 ppm at 20 °C | 8.11 mg/m³ |
Boiling point -4.7 °C at 1 atm: a liquefied gas under its own vapour pressure in cylinders. Critical point 112.9 °C / 25 bar: below this temperature it can be stored as a liquid; cylinder pressure then equals the vapour pressure. Vapour pressure ≈ 2.97 bar at 25 °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 6.73 (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 = 8.11 mg/m³; NDIR reads partial pressure, so readings scale with absolute pressure (value = reading × P/1013) and must be pressure-compensated.
| Hazard class | harmful if inhaled (Acute Tox. 4); greenhouse gas (F-gas Annex I) |
| GHS signal word | Warning |
| CLP classification | Gases under pressure, liquefied gas; H280 Acute toxicity, Category 4, inhalation; H332 |
| Hazard statements | H280: Contains gas under pressure; may explode if heated. H332: Harmful if inhaled. |
| Lower / upper explosion limit | non-flammable |
| Auto-ignition temperature | — |
| Seveso III named substance | no |
| 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) | — |
| OSHA PEL (USA) | — |
| IDLH | — |
Classified Acute Tox. 4 (harmful if inhaled) — unlike SF₆ it is not inert to the body; 3M’s 4-week inhalation NOAEL data underpin an 8-h workplace guideline of 65 ppm (3M). Used at 4–6 % in CO₂/O₂ mixtures in switchgear. Decomposition products in arcs are toxic (COF₂, CF₃CN, HF).
- NDIR (7.5–8.5 µm) or photoacoustic for room monitoring around C4F7N/CO₂ switchgear; density/pressure monitors on compartments as for SF₆ (Reg. 2024/573 Annex I gas, same monitoring exemption logic).
- 3M workplace guideline 65 ppm (8-h); mixture 4–6 % in CO₂/O₂.
| GWP₁₀₀ — IPCC AR6 | — |
| GWP₁₀₀ — IPCC AR4 | — |
| GWP used in Reg. (EU) 2024/573 | 2750 |
| Atmospheric lifetime | 30 years |
| Ozone depletion potential | 0 |
| Main IR absorption band (NDIR) | 7.5–8.5 µm (C–F stretch); 4.4 µm (C≡N stretch, ≈2260 cm⁻¹) |
| Note | AR6 lists a GWP100 of 2,750 for iso-C₃F₇CN (as used by Reg. 2024/573 Annex I, Section 3); 3M technical data cites 2,100 (AR5 method) / 2,240 (AR6 method). |
- F-gas 2024/573 Annex I Section 3 (GWP 2750) — same leak-check / monitoring logic as SF₆ for switchgear
- IEC 62271-4 / CIGRE guidance on handling
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://pubchem.ncbi.nlm.nih.gov/compound/12633773
- 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)
- Regulation (EU) 2024/573, Annex I/III (https://eur-lex.europa.eu/eli/reg/2024/573/oj)
- 3M Novec 4710 Insulating Gas — Technical Data, July 2015 (https://multimedia.3m.com/mws/media/1132124O/technical-data-july-2015.pdf)
- HITRAN/NIST IR band positions (approximate centre of the strongest band used for NDIR; https://hitran.org, https://webbook.nist.gov)