Riboflavin (C17H20N4O6): structure, properties and hazards

Names and identifiers

IUPAC name: 7,8-dimethyl-10-[(2S,3S,4R)-2,3,4,5-tetrahydroxypentyl]benzo[g]pteridine-2,4-dione
Synonyms: vitamin B2, lactoflavin, E101
+ 36 more
Riboflavine, Lactoflavin, Vitamin G, Lactoflavine, Flavaxin, Beflavine, Beflavin, Riboderm, Ribipca, Ribovel, Lactobene, Ribocrisina, Riboflavina, Riboflavinum, Ribotone, Vitaflavine, Flaxain, Ribosyn, Vitamin Bi, Flavin BB, Russupteridine Yellow III, Vitasan B2, HYRE, Bisulase, Riboflavinequinone, 6,7-Dimethyl-9-D-ribitylisoalloxazine, 7,8-Dimethyl-10-ribitylisoalloxazine, Lacto-flavin, Fiboflavin, Dermadram, vitamin-b2, Aqua-Flave, DTXSID8021777, C.I. Food Yellow 15, Vitamin B-2, 7,8-dimethyl-10-[(2S,3S,4R)-2,3,4,5-tetrahydroxypentyl]benzo[g]pteridine-2,4-dione
Molecular formula: C₁₇H₂₀N₄O₆
Empirical formula: C₁₇H₂₀N₄O₆
Molecular weight: 376.4 g/mol
Exact mass: 376.13828
CAS number: 83-88-5
PubChem CID: 493570
Canonical SMILES: CC1=CC2=C(C=C1C)N(C3=NC(=O)NC(=O)C3=N2)CC(C(C(CO)O)O)O
Isomeric SMILES: CC1=CC2=C(C=C1C)N(C3=NC(=O)NC(=O)C3=N2)C[C@@H]([C@@H]([C@@H](CO)O)O)O
InChI: InChI=1S/C17H20N4O6/c1-7-3-9-10(4-8(7)2)21(5-11(23)14(25)12(24)6-22)15-13(18-9)16(26)20-17(27)19-15/h3-4,11-12,14,22-25H,5-6H2,1-2H3,(H,20,26,27)/t11-,12+,14-/m0/s1
InChIKey: AUNGANRZJHBGPY-SCRDCRAPSA-N
Molfile

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

Physical properties

Appearance: Orange to yellow crystals or needles[2]
2 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– ORANGE-YELLOW CRYSTALS. [1] ILO-WHO International Chemical Safety Cards (ICSCs)
–shown Orange to yellow crystals or needles [2] 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. 3158
Odor: Slight odor[2]
Solubility in water: Solubility in water, g/100ml at 25 °C: 0.01[1]
3 values
From ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative source here.
Value As written Source
– Slightly soluble in alcohols; insoluble in lipid solvents [2] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 1090
– In water, of 0.1 g/L at 20 °C; 0.071 g/L and 0.085 g/L at 25 °C [2] Hazardous Substances Data Bank (HSDB)cites Yalkowsky SH, Dannenfelser RM; The AQUASOL dATAbASE of Aqueous Solubility. Ver 5. Tucson, AZ: Univ AZ, College of Pharmacy (1992)
–shown Solubility in water, g/100ml at 25 °C: 0.01 [1] ILO-WHO International Chemical Safety Cards (ICSCs)
log P: -1.46[1]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source
– log Kow = -1.46 [2] Hazardous Substances Data Bank (HSDB)cites Nahum A, Horvath C; J Chromatogr 192: 315-322 (1980)
–shown -1.46 [1] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
–	ORANGE-YELLOW CRYSTALS.	[1] ILO-WHO International Chemical Safety Cards (ICSCs)
–shown	Orange to yellow crystals or needles	[2] 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. 3158

Value	As written	Source
–	Slightly soluble in alcohols; insoluble in lipid solvents	[2] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 1090
–	In water, of 0.1 g/L at 20 °C; 0.071 g/L and 0.085 g/L at 25 °C	[2] Hazardous Substances Data Bank (HSDB)cites Yalkowsky SH, Dannenfelser RM; The AQUASOL dATAbASE of Aqueous Solubility. Ver 5. Tucson, AZ: Univ AZ, College of Pharmacy (1992)
–shown	Solubility in water, g/100ml at 25 °C: 0.01	[1] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
–	log Kow = -1.46	[2] Hazardous Substances Data Bank (HSDB)cites Nahum A, Horvath C; J Chromatogr 192: 315-322 (1980)
–shown	-1.46	[1] ILO-WHO International Chemical Safety Cards (ICSCs)

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: 27
Rings: 3
Aromatic rings: 1
Fraction sp³ carbons (Fsp3): 0.41
H-bond donors: 5
H-bond acceptors: 8 computed here · PubChem 7
Rotatable bonds: 5
TPSA (Å²): 161.6 computed here · PubChem 155
Formal charge: 0
XLogP3: -1.5 PubChem
Complexity: 680 PubChem
Stereocenters: 3 definedCIP: C16: S · C18: S · C20: R
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

C54.25%
H5.36%
N14.89%
O25.51%

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: -1.72 Crippen (Wildman and Crippen 1999)
log S (water solubility): -1.14 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 3.79 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 376.37
log P ≤ 5 (Crippen): -1.72
H-bond donors ≤ 5: 5
H-bond acceptors ≤ 10: 8

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

This chemical does not meet GHS hazard criteria for 98.4% (122 of 124) of all reports.[3]

First aid

Fresh air, rest.[1]
Rinse and then wash skin with water and soap.[1]
First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.[1]

Storage

Well closed.[1]
Solutions of riboflavin should be protected from air and light. Riboflavin tablets should be stored in tight, light-resistant containers at a temperature less than 40 degrees C, preferably between 15-30 degrees C.[2]

Safety data sheets on the supplier’s page: Sigma-Aldrich, LGC Standards, Glixx Labs Inc.

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]ILO-WHO International Chemical Safety Cards (ICSCs) · CC BY 4.0 · 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]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
[5]Human Metabolome Database (HMDB) · 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
[9]EU Food Improvement Agents · Linked only · via PubChem · retrieved 2026-10-14
[10]SpectraBase · 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.

Similar structures

Tanimoto similarity on Morgan fingerprints (radius 2) with RDKit 2026.09, at least 45%.