Lysine (C6H14N2O2): structure, properties and hazards

Names and identifiers

IUPAC name: (2S)-2,6-diaminohexanoic acid
Synonyms: L-lysine, lysine acid, h-Lys-oh
+ 35 more
(S)-Lysine, Aminutrin, alpha-Lysine, (S)-2,6-Diaminohexanoic acid, L-lys, Lisina, Lysinum, (S)-alpha,epsilon-Diaminocaproic acid, LYS (IUPAC abbreviation), L-2,6-Diaminocaproic acid, (+)-S-Lysine, DTXSID6023232, CHEBI:18019, 2,6-diaminohexanoate, 6-ammonio-L-norleucine, K3Z4F929H6, DTXCID403232, (2S)-6-amino-2-azaniumylhexanoate, CHEBI:25094, l lysine, L-Lysine High, RefChem:6459, L-Lysine 7415, L-Lysine High 7416, B05XB03, (2S)-2,6-diaminohexanoate;hydron, L-alpha,epsilon-Diaminocaproic Acid, 200-294-2, (2S)-2,6-diaminohexanoic acid, L-(+)-Lysine, (S)-2,6-Diaminocaproic acid, Hydrolysin, Lysinum [Latin], Lisina [Spanish], L-Norleucine, 6-amino-
Molecular formula: C₆H₁₄N₂O₂
Empirical formula: C₃H₇NO
Molecular weight: 146.19 g/mol
Exact mass: 146.10553
CAS number: 56-87-1
PubChem CID: 5962
Canonical SMILES: C(CCN)CC(C(=O)O)N
Isomeric SMILES: C(CCN)C[C@@H](C(=O)O)N
InChI: InChI=1S/C6H14N2O2/c7-4-2-1-3-5(8)6(9)10/h5H,1-4,7-8H2,(H,9,10)/t5-/m0/s1
InChIKey: KDXKERNSBIXSRK-YFKPBYRVSA-N
Molfile

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

Physical properties

TemperaturePressureDensity

Appearance: Colorless crystals[1]
Solubility in water: In water, 5.84 × 10⁵ mg/L at 27 °C[1]
2 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– Water solubility: >100 g/100 g H20 at 25 °C [1] Hazardous Substances Data Bank (HSDB)cites Gerhartz, W. (exec ed.). Ullmann's Encyclopedia of Industrial Chemistry. 5th ed.Vol A1: Deerfield Beach, FL: VCH Publishers, 1985 to Present., p. VA2 63
–shown In water, 5.84X10+5 mg/L at 27 °C [1] 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. 325
log P: log Kow = -3.05[1]
Vapor pressure: Reported, but no value passed the checks.
The value and why
5.28X10+9 mm Hg at 25 °C /extrapolated/ (outside the plausible range; source [1])

Value	As written	Source
–	Water solubility: >100 g/100 g H20 at 25 °C	[1] Hazardous Substances Data Bank (HSDB)cites Gerhartz, W. (exec ed.). Ullmann's Encyclopedia of Industrial Chemistry. 5th ed.Vol A1: Deerfield Beach, FL: VCH Publishers, 1985 to Present., p. VA2 63
–shown	In water, 5.84X10+5 mg/L at 27 °C	[1] 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. 325

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: 10
Rings: 0
Aromatic rings: 0
Fraction sp³ carbons (Fsp3): 0.83
H-bond donors: 3
H-bond acceptors: 3 computed here · PubChem 4
Rotatable bonds: 5
TPSA (Å²): 89.3
Formal charge: 0
XLogP3: -3 PubChem
Complexity: 106 PubChem
Stereocenters: 1 definedCIP: C6: S
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

C49.30%
H9.65%
N19.16%
O21.89%

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: -0.47 Crippen (Wildman and Crippen 1999)
log S (water solubility): -0.12 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 2.47 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 146.19
log P ≤ 5 (Crippen): -0.47
H-bond donors ≤ 5: 3
H-bond acceptors ≤ 10: 3

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 98.3% (117 of 119) of all reports.[2]

Safety data sheets on the supplier’s page: CymitQuimica, CATO Research Chemicals Inc., Smolecule.

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]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[2]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[3]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[4]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[5]MassBank Europe · 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
·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%.

Isomers in the library

D-Lysine