Quercetin (C15H10O7): structure, properties and hazards

Names and identifiers

IUPAC name: 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxychromen-4-one
Synonyms: flavonoid, sophoretin, meletin
+ 38 more
Sophoretin, Meletin, Xanthaurine, Quercetol, Quercetine, Quertine, 2-(3,4-Dihydroxyphenyl)-3,5,7-trihydroxy-4H-chromen-4-one, Quercitin, 3,3',4',5,7-Pentahydroxyflavone, Quertin, 3,5,7,3',4'-Pentahydroxyflavone, Cyanidelonon 1522, Flavin meletin, T-Gelb bzw. grun 1, C.I. Natural Yellow 10, Cyanidenolon 1522, 2-(3,4-Dihydroxyphenyl)-3,5,7-trihydroxy-4H-1-benzopyran-4-one, C.I. 75670, C.I. Natural red 1, Corvitin, 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxychromen-4-one, Korvitin, Lipoflavon, 3',4',5,7-Tetrahydroxyflavan-3-ol, Flavone, 3,3',4',5,7-pentahydroxy-, NSC 9219, 4H-1-Benzopyran-4-one, 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-, NCI-C60106, 3'-hydroxykaempferol, DTXSID4021218, NSC9219, 3,5,7-Trihydroxy-2-(3,4-dihydroxyphenyl)-4H-chromen-4-on, NSC-9219, 9IKM0I5T1E, CI 75670, CHEBI:16243, Ci-75670, NSC-57655
Molecular formula: C₁₅H₁₀O₇
Empirical formula: C₁₅H₁₀O₇
Molecular weight: 302.23 g/mol
Exact mass: 302.04265
CAS number: 117-39-5
PubChem CID: 5280343
Canonical SMILES: C1=CC(=C(C=C1C2=C(C(=O)C3=C(C=C(C=C3O2)O)O)O)O)O
Isomeric SMILES: C1=CC(=C(C=C1C2=C(C(=O)C3=C(C=C(C=C3O2)O)O)O)O)O
InChI: InChI=1S/C15H10O7/c16-7-4-10(19)12-11(5-7)22-15(14(21)13(12)20)6-1-2-8(17)9(18)3-6/h1-5,16-19,21H
InChIKey: REFJWTPEDVJJIY-UHFFFAOYSA-N
Molfile

Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.

Physical properties

TemperaturePressureDensity

Appearance: Yellow needles (dilute alcohol, +2 water)[2]
2 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– Quercetin appears as yellow needles or yellow powder. Converts to anhydrous form at 203-207 °F. Alcoholic solutions taste very bitter. (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.
–shown Yellow needles (dilute alcohol, +2 water) [2] Hazardous Substances Data Bank (HSDB)cites Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V2: 1570
Melting point: 316.5 °C[2]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source
316 to 317 °C 601 to 603 °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.
316.5 °Cshown 316.5 °C [2] Hazardous Substances Data Bank (HSDB)cites Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V2: 1570
Boiling point: Reported, but no value passed the checks.
The value and why
Sublimes (NTP, 1992) (could not be read; source [1])
Solubility in water: In water, 60 mg/L at 16 °C[2]
4 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– less than 1 mg/mL at 70 °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.
– Very soluble in ether, methanol; soluble in ethanol, acetone, pyridine, acetic acid [2] Hazardous Substances Data Bank (HSDB)cites Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V2: 1570
– Soluble in alcohol and glacial acetic acid; insoluble in water [2] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 14th Edition. John Wiley & Sons, Inc. New York, NY 2001., p. 945
–shown In water, 60 mg/L at 16 °C [2] Hazardous Substances Data Bank (HSDB)cites Seidell A; Solubilities of Organic Compounds. NY,NY: d. Van Norstrand Co., Inc. (1941)

Value	As written	Source
–	Quercetin appears as yellow needles or yellow powder. Converts to anhydrous form at 203-207 °F. Alcoholic solutions taste very bitter. (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.
–shown	Yellow needles (dilute alcohol, +2 water)	[2] Hazardous Substances Data Bank (HSDB)cites Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V2: 1570

Value	As written	Source
316 to 317 °C	601 to 603 °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.
316.5 °Cshown	316.5 °C	[2] Hazardous Substances Data Bank (HSDB)cites Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V2: 1570

Value	As written	Source
–	less than 1 mg/mL at 70 °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.
–	Very soluble in ether, methanol; soluble in ethanol, acetone, pyridine, acetic acid	[2] Hazardous Substances Data Bank (HSDB)cites Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V2: 1570
–	Soluble in alcohol and glacial acetic acid; insoluble in water	[2] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 14th Edition. John Wiley & Sons, Inc. New York, NY 2001., p. 945
–shown	In water, 60 mg/L at 16 °C	[2] Hazardous Substances Data Bank (HSDB)cites Seidell A; Solubilities of Organic Compounds. NY,NY: d. Van Norstrand Co., Inc. (1941)

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: 22
Rings: 3
Aromatic rings: 3
Fraction sp³ carbons (Fsp3): 0
H-bond donors: 5
H-bond acceptors: 7
Rotatable bonds: 1
TPSA (Å²): 131.4 computed here · PubChem 127
Formal charge: 0
XLogP3: 1.5 PubChem
Complexity: 488 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

C59.61%
H3.34%
O37.05%

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: 1.99 Crippen (Wildman and Crippen 1999)
log S (water solubility): -3.44 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 2.54 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 302.24
log P ≤ 5 (Crippen): 1.99
H-bond donors ≤ 5: 5
H-bond acceptors ≤ 10: 7

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: 224 company reports to ECHA. Source [3].

Acute toxicity

H301Toxic if swallowed (97.3% of reports)

Precautionary statements: P264, P270, P301+P316, P321, P330, P405, P501

View all classifications (2)

[3] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for 1.3% (3 of 224) of reports.
[3] European Chemicals Agency (ECHA) · 224 reports · DangerH301

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]

Storage

Quercetin tablets and capsules should be stored at room temp, away from heat, moisture, and direct light.[2]

Safety data sheets on the supplier’s page: Alfa Chemistry, Enamine, Aladdin Scientific.

Always read the supplier’s safety data sheet before working with it.

Spectra

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]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[5]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[6]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[7]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
[8]MassBank Europe · 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.