Diazepam (C16H13ClN2O): structure, properties and hazards

Names and identifiers

IUPAC name: 7-chloro-1-methyl-5-phenyl-3H-1,4-benzodiazepin-2-one
Synonyms: Valium, benzodiazepine, Ansiolisina
+ 36 more
Diazemuls, Apaurin, Faustan, Relanium, Seduxen, Sibazon, Stesolid, Bialzepam, Ceregulart, Neurolytril, Serenamin, Valrelease, Alboral, Ansiolin, Apozepam, Atensine, Calmpose, Cercine, Lembrol, Morosan, Setonil, Sonacon, Stesolin, Tranimul, Atilen, Duxen, Eridan, Levium, Paxate, Paxel, Vivol, Noan, Methyldiazepinone, Calmocitene, Condition, Diacepan
Molecular formula: C₁₆H₁₃ClN₂O
Empirical formula: C₁₆H₁₃ClN₂O
Molecular weight: 284.74 g/mol
Exact mass: 284.07164
CAS number: 439-14-5
PubChem CID: 3016
Canonical SMILES: CN1C(=O)CN=C(C2=C1C=CC(=C2)Cl)C3=CC=CC=C3
Isomeric SMILES: CN1C(=O)CN=C(C2=C1C=CC(=C2)Cl)C3=CC=CC=C3
InChI: InChI=1S/C16H13ClN2O/c1-19-14-8-7-12(17)9-13(14)16(18-10-15(19)20)11-5-3-2-4-6-11/h2-9H,10H2,1H3
InChIKey: AAOVKJBEBIDNHE-UHFFFAOYSA-N
Molfile

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

Physical properties

TemperaturePressureDensity

Appearance: Colorless to light yellow crysytals[2]
3 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– Diazepam is an off-white to yellow crystalline powder. Practically odorless. Tasteless at first with a bitter aftertaste. (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 Colorless to light yellow crysytals [2] Hazardous Substances Data Bank (HSDB)cites Physicians Desk Reference 64th ed. PDR Network, LLC, Montvale, NJ. 2010, p. 2880
– Slightly yellowish crystalline powder [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. 389
Odor: Practically no odor[2]
Melting point: 125 to 126 °C (257 to 259 °F, NTP 1992)[1]
Solubility in water: In water, 66 mg/L at 25 °C[2]
5 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– less than 1 mg/mL at 68 °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 g/2 mL chloroform; 1 g/39 mL ether [2] Hazardous Substances Data Bank (HSDB)cites Osol, A. (ed.). Remington's Pharmaceutical Sciences. 16th ed. Easton, Pennsylvania: Mack Publishing Co., 1980., p. 1007
– Sparingly soluble in propylene glycol; approx 62.5 mg/mL alcohol at 25 °C [2] Hazardous Substances Data Bank (HSDB)cites McEvoy, G.K. (ed.). American Hospital Formulary Service-Drug Information 19 98. Bethesda, MD: American Society of Health-System Pharmacists, Inc. 1998 (Plus Supplements)., p. 1944
– One gram of diazepam dissolves in about 350 mL of water, in approximately 15 mL of 95% ethanol, or in approximately 2 mL of chloroform. [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. 389
–shown In water, 66 mg/L at 25 °C [2] 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. 1031
log P: log Kow = 2.82[2]

Value	As written	Source
–	Diazepam is an off-white to yellow crystalline powder. Practically odorless. Tasteless at first with a bitter aftertaste. (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	Colorless to light yellow crysytals	[2] Hazardous Substances Data Bank (HSDB)cites Physicians Desk Reference 64th ed. PDR Network, LLC, Montvale, NJ. 2010, p. 2880
–	Slightly yellowish crystalline powder	[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. 389

Value	As written	Source
–	less than 1 mg/mL at 68 °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 g/2 mL chloroform; 1 g/39 mL ether	[2] Hazardous Substances Data Bank (HSDB)cites Osol, A. (ed.). Remington's Pharmaceutical Sciences. 16th ed. Easton, Pennsylvania: Mack Publishing Co., 1980., p. 1007
–	Sparingly soluble in propylene glycol; approx 62.5 mg/mL alcohol at 25 °C	[2] Hazardous Substances Data Bank (HSDB)cites McEvoy, G.K. (ed.). American Hospital Formulary Service-Drug Information 19 98. Bethesda, MD: American Society of Health-System Pharmacists, Inc. 1998 (Plus Supplements)., p. 1944
–	One gram of diazepam dissolves in about 350 mL of water, in approximately 15 mL of 95% ethanol, or in approximately 2 mL of chloroform.	[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. 389
–shown	In water, 66 mg/L at 25 °C	[2] 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. 1031

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: 3
Aromatic rings: 2
Fraction sp³ carbons (Fsp3): 0.12
H-bond donors: 0
H-bond acceptors: 2
Rotatable bonds: 1
TPSA (Å²): 32.7
Formal charge: 0
XLogP3: 3 PubChem
Complexity: 403 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

C67.49%
H4.60%
Cl12.45%
N9.84%
O5.62%

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: 3.15 Crippen (Wildman and Crippen 1999)
log S (water solubility): -3.97 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 2.12 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 284.75
log P ≤ 5 (Crippen): 3.15
H-bond donors ≤ 5: 0
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

Danger

Most widely reported: 85 company reports to ECHA. Source [3].

Acute toxicity

H301Toxic if swallowed (96.5% of reports)
H311Toxic in contact with skin (77.6% of reports)

Precautionary statements: P262, P264, P270, P280, P301+P316, P302+P352, P316, P321, P330, P361+P364, P405, P501

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

Store in tight container as defined in the usp-nf. This material should be handled and stored per label instructions to ensure product integrity.[2]
Diazepam injection should be protected from light and stored at 15-30 °C; freezing should be avoided. Diazepam tablets and extended-release capsules should be stored in tight, light-resistant containers at 15-30 °C. Diazepam oral solution and oral concentrate solution should be stored at 15-30 °C. ... Diazepam rectal gel should be stored at a controlled room temperature of 25 deg but may be exposed to temperatures ranging from 15-30 °C.[2]

Incompatibilities

A significant interaction exists between diazepam and infusion fluid containers constructed of pvc plastics, due to absorption of diazepam into the pvc matrix.[2]

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]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
[5]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[6]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[7]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[8]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
[9]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.