Stearic acid
Athanor · official
C18H36O2 · 284.5 g/mol
IUPAC name: octadecanoic acid
Also called octadecanoic acid, C18:0, stearate
WarningCauses skin irritationNames and identifiers
- IUPAC name
- octadecanoic acid
- Synonyms
- octadecanoic acid, C18:0, stearate
+ 38 more
Octadecanoic acid, n-Octadecanoic acid, Stearophanic acid, Stearex Beads, 1-Heptadecanecarboxylic acid, Pearl stearic, Cetylacetic acid, Industrene R, Octadecansaeure, Stearinsaeure, Vanicol, Hydrofol Acid 150, Century 1240, Glycon DP, Glycon TP, Humko Industrene R, Formula 300, Hydrofol 1895, Hystrene 7018, Hystrene 9718, Glycon S-80, Glycon S-90, octadecoic acid, Tegostearic 254, Tegostearic 255, Tegostearic 272, Hystrene 80, Hydrofol acid 1655, Hydrofol acid 1855, Industrene 5016, Dar-chem 14, Emersol 120, Emersol 132, Hystrene 4516, Hystrene 5016, Groco 54, Groco 55, Groco 55L
- Molecular formula
- C18H36O2
- Empirical formula
- C9H18O
- Molecular weight
- 284.5 g/mol
- Exact mass
- 284.27153
- CAS number
- 57-11-4
- PubChem CID
- 5281
- Canonical SMILES
- CCCCCCCCCCCCCCCCCC(=O)O
- Isomeric SMILES
- CCCCCCCCCCCCCCCCCC(=O)O
- InChI
- InChI=1S/C18H36O2/c1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18(19)20/h2-17H2,1H3,(H,19,20)
- InChIKey
- QIQXTHQIDYTFRH-UHFFFAOYSA-N
- Molfile
Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.
Physical properties
TemperaturePressureDensity
- Appearance
- Colorless, wax-like solid[5]
6 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source – Stearic acid is a white solid with a mild odor. Floats on water. (USCG, 1999) [1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office. – Liquid; Liquid; Other Solid; Dry Powder; Liquid; Other Solid; Dry Powder; Wet Solid; Other Solid; Large Crystals; Large Crystals; Other Solid [2] EPA Chemical Data Reporting (CDR) – WHITE CRYSTALS OR POWDER WITH CHARACTERISTIC ODOUR. [3] ILO-WHO International Chemical Safety Cards (ICSCs) – White solid with a mild odor. [4] Occupational Safety and Health Administration (OSHA) –shown Colorless, wax-like solid [5] Hazardous Substances Data Bank (HSDB)cites Larranaga, M.D., Lewis, R.J. Sr., Lewis, R.A.; Hawley's Condensed Chemical Dictionary 16th Edition. John Wiley & Sons, Inc. Hoboken, NJ 2016., p. 1273 – White amorphous solid or leaflets [5] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 12th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2012., p. V5: 4069 - Odor
- Slight odor suggesting tallow[5]
- Melting point
- 69.3 °C (156.7 °F, NTP 1992)[1]
4 values
4 of 4 sources agree on it (most common value).
Value As written Source 69.3 °Cshown 156.7 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina. 69 to 72 °C 69-72 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs) 69.3 °C 156.7 °F [4] Occupational Safety and Health Administration (OSHA) 69.3 °C 69.3 °C [6] PAC Chemical Database, U.S. Department of Energy - Boiling point
- 383 °C (721 °F) at 760 mmHg (NTP, 1992)[1]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source 383 °Cshown 721 °F at 760 mmHg (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina. 383 °C 721 °F [4] Occupational Safety and Health Administration (OSHA) - Density
- 0.9408 @ 20°C[6]
4 values
2 of 4 sources agree on it (most common value).
Value As written Source – 0.86 at 68 °F (USCG, 1999) - Less dense than water [1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office. – Relative density (water = 1): 0.94-0.83 [3] ILO-WHO International Chemical Safety Cards (ICSCs) – 0.86 [4] Occupational Safety and Health Administration (OSHA) –shown 0.9408 @ 20°C [6] PAC Chemical Database, U.S. Department of Energy - Solubility in water
- Solubility in water: none[3]
6 values
From ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative source here.
Value As written Source – 1 to 10 mg/mL at 73 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina. – In water, 0.568 mg/L at 25 °C [5] Hazardous Substances Data Bank (HSDB)cites Robb ID; Aust J Chem 19: 2281-84 (1966) – In water, 0.597 mg/L at 25 °C [5] Hazardous Substances Data Bank (HSDB)cites Yalkowsky, S.H., He, Yan., Handbook of Aqueous Solubility Data: An Extensive Compilation of Aqueous Solubility Data for Organic Compounds Extracted from the AQUASOL dATAbASE. CRC Press LLC, Boca Raton, FL. 2003., p. 1119 – Insoluble in water [5] Hazardous Substances Data Bank (HSDB)cites Larranaga, M.D., Lewis, R.J. Sr., Lewis, R.A.; Hawley's Condensed Chemical Dictionary 16th Edition. John Wiley & Sons, Inc. Hoboken, NJ 2016., p. 1273 – For more Solubility (Complete) data for Stearic acid (6 total), please visit the HSDB record page. [5] Hazardous Substances Data Bank (HSDB) –shown Solubility in water: none [3] ILO-WHO International Chemical Safety Cards (ICSCs) - log P
- log Kow = 8.23[5]
- Vapor pressure
- Vapor pressure, Pa at 174 °C: 133[3]
7 values
4 of 4 sources agree on it (most common value).
Value As written Source 1 mmHg 1 mmHg at 344.7 °F [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina. 5 mmHg 5 mmHg at 408.2 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina. 1 mmHg Vapor pressure = 1 mm Hg at 173.1 °C [5] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 12th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2012., p. V5: 4069 7.22e-7 mmHg 7.22X10-7 mm Hg at 25 °C (ext) [5] Hazardous Substances Data Bank (HSDB)cites Daubert, T.E., R.P. Danner. Physical and Thermodynamic Properties of Pure Chemicals Data Compilation. Washington, D.C.: Taylor and Francis, 1989. 0.998 mmHgshown Vapor pressure, Pa at 174 °C: 133 [3] ILO-WHO International Chemical Safety Cards (ICSCs) 1 mmHg 1 mmHg at 344.7 °F [4] Occupational Safety and Health Administration (OSHA) 5 mmHg 5 mmHg at 408.2 °F [4] Occupational Safety and Health Administration (OSHA) - Flash point
- 196 °C[3]
5 values
4 of 4 sources agree on it (most common value).
Value As written Source 196 °C 385 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina. 113 °C 113 °C (235 °F) - closed cup [5] Hazardous Substances Data Bank (HSDB)cites Sigma-Aldrich; Safety Data Sheet for Stearic acid. Product Number: 85679, Version 5.6 (Revision Date 07/21/2015). Available from, as of November 16, 2017: https://www.sigmaaldrich.com/safety-center.html 196 °C 385 °F (196 dec C) (closed cup) [5] Hazardous Substances Data Bank (HSDB)cites National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 325-104 196 °Cshown 196 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs) 196 °C 385 °F [4] Occupational Safety and Health Administration (OSHA) - Autoignition temperature
- 395 °C[3]
3 values
3 of 3 sources agree on it (most common value).
Value As written Source 395 °C 743 °F (USCG, 1999) [1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office. 395 °C 743 °F [5] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 3299 395 °Cshown 395 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs) - Viscosity
- Reported, but no value passed the checks.
The value and why
- 9.87 mPa.sec (cP) at 70 °C (could not be read; source [5])
- Refractive index
- Index of refraction: 1.4299 at 80 °C[5]
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
- 20
- Rings
- 0
- Aromatic rings
- 0
- Fraction sp³ carbons (Fsp3)
- 0.94
- H-bond donors
- 1
- H-bond acceptors
- 1 computed here · PubChem 2
- Rotatable bonds
- 16
- TPSA (Ų)
- 37.3
- Formal charge
- 0
- XLogP3
- 7.4 PubChem
- Complexity
- 202 PubChem
- Stereocenters
- None
- Double-bond geometry
- None specified
- Point group
- C1 of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)
Elemental analysis
- C76.00%
- H12.76%
- O11.25%
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
- 6.33 Crippen (Wildman and Crippen 1999)
- log S (water solubility)
- -4.54 ESOL (Delaney 2004), log mol/L
- Synthetic accessibility
- 1.67 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)
Drug-likeness: Lipinski’s rule of five
- Molecular weight ≤ 500: 284.48
- log P ≤ 5 (Crippen): 6.33
- H-bond donors ≤ 5: 1
- H-bond acceptors ≤ 10: 1
Breaks 1 of the 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
Warning
Most widely reported: 2,057 company reports to ECHA. Source [7].
- Harmful or irritant
- H315Causes skin irritation (25.1% of reports)
Precautionary statements: P264, P280, P302+P352, P321, P332+P317, P362+P364
View all classifications (3)
- [7] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for 68.3% (1405 of 2057) of all reports.
- [7] European Chemicals Agency (ECHA) · 2,057 reports · WarningH315
- [7] European Chemicals Agency (ECHA) · DangerH301, H400
Exposure limits
First aid
- Eyes: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. Immediately transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop. Skin: Immediately flood affected skin with water while removing and isolating all contaminated clothing.[1]
- Fresh air, rest.[3]
- Remove contaminated clothes. Rinse and then wash skin with water and soap.[3]
- First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.[3]
Incompatibilities
- Incompatible materials: Bases, oxidizing agents, reducing agents.[5]
Safety data sheets on the supplier’s page: AbaChemScene, Alfa Chemistry, Thermo Fisher Scientific.
Always read the supplier’s safety data sheet before working with it.
Spectra
- NMRHazardous Substances Data Bank (HSDB) · NMRShiftDB
- 1H NMRHuman Metabolome Database (HMDB) (Varian · 500 MHz · CDCl3) · Human Metabolome Database (HMDB) (500 MHz · CDCl3) · Human Metabolome Database (HMDB) (JEOL · 90 MHz · CDCl3) · Human Metabolome Database (HMDB) (Bruker · CDCl3) · SpectraBase (BRUKER AC-300)
- 13C NMRHuman Metabolome Database (HMDB) (Varian · 25.16 MHz · CDCl3) · Human Metabolome Database (HMDB) (Bruker · CDCl3) · SpectraBase
- 1H-13C NMRHuman Metabolome Database (HMDB) (Bruker · 600 MHz · CDCl3)
- GC-MSHuman Metabolome Database (HMDB) (GC-MS) · Human Metabolome Database (HMDB) (EI-B · positive) · Human Metabolome Database (HMDB) (EI-B · positive) · Human Metabolome Database (HMDB) (GC-EI-TOF · positive) · Human Metabolome Database (HMDB) (GC-EI-TOF · positive) · Human Metabolome Database (HMDB) (GC-EI-TOF · positive)
- MS-MSHuman Metabolome Database (HMDB) (Negative) · Human Metabolome Database (HMDB) (Negative) · Human Metabolome Database (HMDB) (Negative) · Human Metabolome Database (HMDB) (Negative) · Human Metabolome Database (HMDB) (Quattro_QQQ · Negative) · Human Metabolome Database (HMDB) (Quattro_QQQ · Negative)
- LC-MSMassBank Europe (Agilent 6560 QTOF · LC-ESI-QTOF · NEGATIVE) · MassBank Europe (Agilent 6560 QTOF · LC-ESI-QTOF · NEGATIVE) · MassBank Europe (maXis plus UHR-ToF-MS, Bruker Daltonics · LC-ESI-QTOF · NEGATIVE) · MassBank Europe (maXis plus UHR-ToF-MS, Bruker Daltonics · LC-ESI-QTOF · NEGATIVE) · MassBank Europe (Bruker impact HD · LC-ESI-QTOF · NEGATIVE) · MassBank Europe (Bruker impact HD · LC-ESI-QTOF · NEGATIVE)
- Other MSHazardous Substances Data Bank (HSDB) · MassBank Europe (JEOL JMS-DX-300 · EI-B · POSITIVE) · MassBank Europe (JEOL JMS-DX-300 · EI-B · POSITIVE) · MassBank of North America (MoNA) (ESI-TOF · negative) · MassBank of North America (MoNA) (ESI-TOF · negative) · MassBank of North America (MoNA) (positive)
- UVHazardous Substances Data Bank (HSDB)
- IRHazardous Substances Data Bank (HSDB)
- FTIRSpectraBase (MELT-BETWEEN SALTS)
- ATR-IRSpectraBase (Bio-Rad FTS · ATR-Neat (DuraSamplIR II))
- Vapor Phase IRSpectraBase (DIGILAB FTS-14 · Vapor Phase)
- RamanSpectraBase (Bruker MultiRAM Stand Alone FT-Raman Spectrometer · FT-Raman)
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]EPA Chemical Data Reporting (CDR) · Public domain (US EPA) · via PubChem · retrieved 2026-10-14
- [3]ILO-WHO International Chemical Safety Cards (ICSCs) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
- [4]Occupational Safety and Health Administration (OSHA) · Public domain (US DOL) · via PubChem · retrieved 2026-10-14
- [5]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
- [6]PAC Chemical Database, U.S. Department of Energy · Public domain (US DOE) · via PubChem · retrieved 2026-10-14
- [7]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
- [8]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
- [9]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
- [10]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
- [11]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
- [12]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
- [13]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.