DangerExtremely flammable gas · Contains gas under pressure; may explode if heatedNames and identifiers
- IUPAC name
- cyclobutane
- Synonyms
- Tetramethylene, UNII-5X619RB2CY, HSDB 58
+ 28 more
5X619RB2CY, EINECS 206-014-5, DTXSID2059772, CHEBI:30377, RefChem:5716, DTXCID6037853, 206-014-5, UN2601, Cyclobutane [UN2601] [Flammable gas], CYCLOBUTANE [MI], cyclobutane, tetramethylene, SCHEMBL893, CYCLOBUTANE [HSDB], SCHEMBL1997, SCHEMBL2088, SCHEMBL4056, SCHEMBL102953, SCHEMBL102954, SCHEMBL143009, SCHEMBL958835, SCHEMBL3000562, SCHEMBL7689963, AKOS003632078, UN 2601, DB-307768, NS00021102, InChI=1/C4H8/c1-2-4-3-1/h1-4H, Q80232
- Molecular formula
- C4H8
- Empirical formula
- CH2
- Molecular weight
- 56.11 g/mol
- Exact mass
- 56.06260
- CAS number
- 287-23-0
- PubChem CID
- 9250
- Canonical SMILES
- C1CCC1
- Isomeric SMILES
- C1CCC1
- InChI
- InChI=1S/C4H8/c1-2-4-3-1/h1-4H2
- InChIKey
- PMPVIKIVABFJJI-UHFFFAOYSA-N
- Molfile
Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.
Physical properties
- Appearance
- Colorless gas[2]
2 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source – Gas that condenses to a liquid at 55 °F. Insoluble in water. Soluble in alcohol, acetone and ether. Under prolonged exposure to fire or intense heat the containers may rupture violently and rocket. [1] CAMEO Chemicals –shown Colorless gas [2] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 12th ed. New York, NY: Van Nostrand Rheinhold Co., 1993, p. 336 - Vapor pressure
- 1.18 × 10³ mmHg @ 25 °C[2]
- Flash point
- BELOW 10 °C (50 °F) Closed Cup[2]
Each value as its source reports it, with the source's number after it (listed under References). Where several sources report a property, the row shows the value most of them agree on, the rule the app uses; open the values to see every one.
Calculated
- Heavy atoms
- 4
- Rings
- 1
- Aromatic rings
- 0
- Fraction sp³ carbons (Fsp3)
- 1
- H-bond donors
- 0
- H-bond acceptors
- 0
- Rotatable bonds
- 0
- TPSA (Ų)
- 0
- Formal charge
- 0
- XLogP3
- 2.5 PubChem
- Complexity
- 8 PubChem
- Stereocenters
- None
- Double-bond geometry
- None specified
- Point group
- D2d of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)
Elemental analysis
- C85.63%
- H14.37%
Isotope pattern
Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.
Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.
Predicted
- log P
- 1.56 Crippen (Wildman and Crippen 1999)
- log S (water solubility)
- -1.17 ESOL (Delaney 2004), log mol/L
- Synthetic accessibility
- 1 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)
Drug-likeness: Lipinski’s rule of five
- Molecular weight ≤ 500: 56.11
- log P ≤ 5 (Crippen): 1.56
- H-bond donors ≤ 5: 0
- H-bond acceptors ≤ 10: 0
Passes all four rules.
¹³C NMR shifts, predicted
Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.
Safety
Danger
Most widely reported: 71 company reports to ECHA. Source [3].
- Flammable
- Compressed gas
- H220Extremely flammable gas
- H280Contains gas under pressure; may explode if heated
Precautionary statements: P203, P210, P222, P280, P377, P381, P403, P410+P403
First aid
- Excerpt from ERG Guide 115 [Gases - Flammable (Including Refrigerated Liquids)]: Refer to the "General First Aid" section. Specific First Aid: Clothing frozen to the skin should be thawed before being removed. In case of contact with liquefied gas, only medical personnel should attempt thawing frosted parts. In case of burns, immediately cool affected skin for as long as possible with cold water. Do not remove clothing if adhering to skin. (ERG, 2024)[1]
- General First Aid: · Call 911 or emergency medical service. · Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination. · Move victim to fresh air if it can be done safely. · Administer oxygen if breathing is difficult. · If victim is not breathing: -- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance. -- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped…[4]
Safety data sheets on the supplier’s page: Smolecule, AKos Consulting & Solutions, RR Scientific.
Always read the supplier’s safety data sheet before working with it.
Spectra
- NMRNMRShiftDB
- 13C NMRSpectraBase
- GC-MSNIST Mass Spectrometry Data Center · NIST Mass Spectrometry Data Center · SpectraBase (CH4)
- Other MSHazardous Substances Data Bank (HSDB)
- IRHazardous Substances Data Bank (HSDB)
Experimental spectra held by these sources; each link opens the source's own record.
Literature
Reading PubChem, OpenAlex and GSRS…
Bioactivity
Reading ChEMBL…
References
- [1]CAMEO Chemicals · Public domain (NOAA) · via PubChem · retrieved 2026-10-14
- [2]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
- [3]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
- [4]Emergency Response Guidebook (ERG) · Public domain (US DOT) · via PubChem · retrieved 2026-10-14
- [5]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
- [6]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
- [7]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
- ·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
- ·Literature on PubChem
Data last updated 2026-10-14.