Niacin
Athanor · official
C6H5NO2 · 123.11 g/mol
IUPAC name: pyridine-3-carboxylic acid
Also called nicotinic acid, vitamin B3, Niaspan, pyridine-3-carboxylic acid
WarningCauses serious eye irritationNames and identifiers
- IUPAC name
- pyridine-3-carboxylic acid
- Synonyms
- nicotinic acid, vitamin B3, Niaspan
+ 36 more
pyridine-3-carboxylic acid, Pyridine-3-carboxylic acid, 3-pyridinecarboxylic acid, 3-Carboxypyridine, Akotin, wampocap, Apelagrin, Pellagrin, Daskil, Efacin, Pelonin, Linic, Nicyl, nicolar, Nicotinipca, Nicacid, Nicangin, Niconacid, Diacin, Nyclin, Acidum nicotinicum, nicamin, Vitaplex N, Nico-Span, Direktan, Nicodelmine, Nicovasen, Pellagramin, Bionic, Naotin, Peviton, Niac, Nicosan 3, Davitamon PP, nicobid, nicocap
- Molecular formula
- C6H5NO2
- Empirical formula
- C6H5NO2
- Molecular weight
- 123.11 g/mol
- Exact mass
- 123.03203
- CAS number
- 59-67-6
- PubChem CID
- 938
- Canonical SMILES
- C1=CC(=CN=C1)C(=O)O
- Isomeric SMILES
- C1=CC(=CN=C1)C(=O)O
- InChI
- InChI=1S/C6H5NO2/c8-6(9)5-2-1-3-7-4-5/h1-4H,(H,8,9)
- InChIKey
- PVNIIMVLHYAWGP-UHFFFAOYSA-N
- Molfile
Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.
Physical properties
TemperaturePressureDensity
- Appearance
- Colorless needles[4]
4 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source – Nicotinic acid is an odorless white crystalline powder with a feebly acid taste. pH (saturated aqueous solution) 2.7. pH (1.3% solution) 3-3.5. (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. – Dry Powder [2] EPA Chemical Data Reporting (CDR) – WHITE CRYSTALS OR CRYSTALLINE POWDER. [3] ILO-WHO International Chemical Safety Cards (ICSCs) –shown Colorless needles [4] 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. 966 - Odor
- Odorless[4]
- Melting point
- 236.6 °C[3]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source 236 °C 457 °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. 236.6 °Cshown 236.6 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs) - Boiling point
- Reported, but no value passed the checks.
The value and why
- Sublimes (NTP, 1992) (could not be read; source [1])
- Density
- 1.473 (NTP, 1992) - Denser than water[1]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source –shown 1.473 (NTP, 1992) - Denser than water [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. – 1.5 g/cm³ [3] ILO-WHO International Chemical Safety Cards (ICSCs) - Solubility in water
- Solubility in water, g/100ml at 20 °C: 1.8 (moderate)[3]
4 values
From ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative source here.
Value As written Source – 10 to 50 mg/mL at 63 °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, 1.8X10+4 mg/L at 20 °C [4] Hazardous Substances Data Bank (HSDB)cites Yalkowsky, S.H., He, Yan, Jain, P. Handbook of Aqueous Solubility Data Second Edition. CRC Press, Boca Raton, FL 2010, p. 227 – Soluble in alcohol, insoluble in most lipid solvents [4] 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. 966 –shown Solubility in water, g/100ml at 20 °C: 1.8 (moderate) [3] ILO-WHO International Chemical Safety Cards (ICSCs) - log P
- -2.43[3]
2 values
Sources disagree; from ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative.
Value As written Source – log Kow = 0.36 [4] Hazardous Substances Data Bank (HSDB)cites Sangster J; LOGKOW Databank. Sangster Research Lab., Montreal, Quebec, Canada (1993) –shown -2.43 [3] ILO-WHO International Chemical Safety Cards (ICSCs) - pKa
- Reported, but no value passed the checks.
The 2 values and why
- kb1 = 1.50X10-5 (could not be read; source [4])
- kb2 = 1.04X10-12 (in water at 20 °C) (could not be read; source [4])
- Flash point
- 193 °C c.c.[3]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source 193 °C 193 °C (379 °F) - closed cup [4] Hazardous Substances Data Bank (HSDB)cites Sigma-Aldrich; Safety Data Sheet for Nicotinic acid. Product Number: N4126, Version 4.11 (Revision Date 09/22/2017). Available from, as of July 18, 2018: https://www.sigmaaldrich.com/safety-center.html 193 °Cshown 193 °C c.c. [3] ILO-WHO International Chemical Safety Cards (ICSCs) - Autoignition temperature
- 580 °C[3]
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
- 9
- Rings
- 1
- Aromatic rings
- 1
- Fraction sp³ carbons (Fsp3)
- 0
- H-bond donors
- 1
- H-bond acceptors
- 2 computed here · PubChem 3
- Rotatable bonds
- 1
- TPSA (Ų)
- 50.2
- Formal charge
- 0
- XLogP3
- 0.4 PubChem
- Complexity
- 114 PubChem
- Stereocenters
- None
- Double-bond geometry
- None specified
- Point group
- Cs of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)
Elemental analysis
- C58.54%
- H4.09%
- N11.38%
- O25.99%
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
- 0.78 Crippen (Wildman and Crippen 1999)
- log S (water solubility)
- -1.52 ESOL (Delaney 2004), log mol/L
- Synthetic accessibility
- 1.59 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)
Drug-likeness: Lipinski’s rule of five
- Molecular weight ≤ 500: 123.11
- log P ≤ 5 (Crippen): 0.78
- H-bond donors ≤ 5: 1
- H-bond acceptors ≤ 10: 2
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
Warning
Most widely reported: 554 company reports to ECHA. Source [5].
- Harmful or irritant
- H319Causes serious eye irritation (99.8% of reports)
Precautionary statements: P264+P265, P280, P305+P351+P338, P337+P317
View all classifications (2)
- [5] European Chemicals Agency (ECHA) · 554 reports · WarningH319
- [4] Hazardous Substances Data Bank (HSDB) · WarningH319, H402
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]
- Rinse skin with plenty of water or shower.[3]
- Rinse with plenty of water (remove contact lenses if easily possible).[3]
Storage
- Store in an area without drain or sewer access. Separated from strong acids, bases and oxidants.[3]
- Keep container tightly closed in a dry and well-ventilated place. Light sensitive.[4]
- Niacin should be stored in well-closed, light-resistant containers at 20-25 °C. When stored under these conditions, Niaspan extended-release and Niacor immediate-release tablets are stable for 3 and 2 years, respectively, after the date of manufacture. The fixed-combination preparation containing extended-release niacin and lovastatin (Advicor) should be stored at room temperature (20-25 °C).[4]
Incompatibilities
- Incompatible materials: Strong oxidizing agents.[4]
Safety data sheets on the supplier’s page: AbMole Bioscience, LGC Standards, DC Chemicals.
Always read the supplier’s safety data sheet before working with it.
Spectra
- NMRHazardous Substances Data Bank (HSDB) · NMRShiftDB
- 1H NMRHuman Metabolome Database (HMDB) (Bruker · 600 MHz · Water) · Human Metabolome Database (HMDB) (JEOL · 400 MHz · DMSO-d6) · Human Metabolome Database (HMDB) (Bruker · D2O) · SpectraBase
- 13C NMRHuman Metabolome Database (HMDB) (JEOL · 22.53 MHz · DMSO-d6) · Human Metabolome Database (HMDB) (Bruker · D2O) · SpectraBase
- 15N NMRSpectraBase
- 17O NMRSpectraBase
- 1H-1H NMRHuman Metabolome Database (HMDB)
- 1H-13C NMRHuman Metabolome Database (HMDB) (Bruker · 600 MHz · Water)
- GC-MSHuman Metabolome Database (HMDB) (GC-MS) · 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) · Human Metabolome Database (HMDB) (GC-EI-TOF · positive)
- MS-MSHuman Metabolome Database (HMDB) (Quattro_QQQ · Positive) · Human Metabolome Database (HMDB) (Quattro_QQQ · Positive) · Human Metabolome Database (HMDB) (Quattro_QQQ · Positive) · Human Metabolome Database (HMDB) (Positive) · Human Metabolome Database (HMDB) (Negative) · Human Metabolome Database (HMDB) (Negative)
- LC-MSMassBank Europe (maXis (Bruker Daltonics) · LC-ESI-QTOF · POSITIVE) · MassBank Europe (maXis (Bruker Daltonics) · LC-ESI-QTOF · POSITIVE) · MassBank Europe (maXis (Bruker Daltonics) · LC-ESI-QTOF · POSITIVE) · MassBank Europe (maXis (Bruker Daltonics) · LC-ESI-QTOF · POSITIVE) · MassBank Europe (maXis (Bruker Daltonics) · LC-ESI-QTOF · POSITIVE) · MassBank Europe (API3000, Applied Biosystems · LC-ESI-QQ · NEGATIVE)
- Other MSHazardous Substances Data Bank (HSDB) · MassBank Europe (HITACHI M-80 · EI-B · POSITIVE) · MassBank of North America (MoNA) (TQD, Waters · Flow-injection QqQ/MS · ESI) · MassBank of North America (MoNA) (TQD, Waters · Flow-injection QqQ/MS · ESI) · MassBank of North America (MoNA) (TQD, Waters · Flow-injection QqQ/MS · ESI)
- UVHazardous Substances Data Bank (HSDB)
- UV-VISSpectraBase
- IRHazardous Substances Data Bank (HSDB)
- FTIRSpectraBase (Bruker IFS 85 · KBr-Pellet)
- ATR-IRSpectraBase (Bio-Rad FTS · ATR-Neat (DuraSamplIR II))
- Vapor Phase IRSpectraBase (DIGILAB FTS-14 · Vapor Phase)
- RamanSpectraBase (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]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
- [5]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
- [6]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
- [7]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
- [8]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
- [9]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
- [10]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
- [11]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.