Benzothiazole (C7H5NS): structure, properties and hazards

Names and identifiers

IUPAC name: 1,3-benzothiazole
Synonyms: 1,3-Benzothiazole, Benzosulfonazole, 1-Thia-3-azaindene
+ 35 more
Vangard BT, USAF EK-4812, FEMA No. 3256, FEMA Number 3256, DTXSID7024586, O-2857, CHEBI:45993, G5BW2593EP, NSC-8040, DTXCID204586, RefChem:118563, 202-396-2, BENZO[D]THIAZOLE, benzothiazol, MFCD00005775, BT, benzthiazole, CAS-95-16-9, CCRIS 7893, HSDB 2796, NSC 8040, EINECS 202-396-2, BRN 0109468, UNII-G5BW2593EP, s-benzothiazole, AI3-05742, Benzothiazole, 96%, 1,3-Benzothiazole #, Benzothiazole (Standard), BENZOTHIAZOLE [MI], Epitope ID:138946, EC 202-396-2, SCHEMBL3484, SCHEMBL8430, BENZOTHIAZOLE [FHFI]
Molecular formula: C₇H₅NS
Empirical formula: C₇H₅NS
Molecular weight: 135.19 g/mol
Exact mass: 135.01427
CAS number: 95-16-9
PubChem CID: 7222
Canonical SMILES: C1=CC=C2C(=C1)N=CS2
Isomeric SMILES: C1=CC=C2C(=C1)N=CS2
InChI: InChI=1S/C7H5NS/c1-2-4-7-6(3-1)8-5-9-7/h1-5H
InChIKey: IOJUPLGTWVMSFF-UHFFFAOYSA-N
Molfile

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

Physical properties

TemperaturePressureDensity

Appearance: Yellow liquid[2]
2 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– Liquid [1] EPA Chemical Data Reporting (CDR)
–shown Yellow liquid [2] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 12th ed. New York, NY: Van Nostrand Rheinhold Co., 1993, p. 132
Odor: Unpleasant odor[2]
Melting point: 2 °C[3]
Boiling point: 231 °C @760 [mmHg][3]
Density: 1.238 @25 °C[3]

Value	As written	Source
–	Liquid	[1] EPA Chemical Data Reporting (CDR)
–shown	Yellow liquid	[2] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 12th ed. New York, NY: Van Nostrand Rheinhold Co., 1993, p. 132

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: 2
Aromatic rings: 2
Fraction sp³ carbons (Fsp3): 0
H-bond donors: 0
H-bond acceptors: 2
Rotatable bonds: 0
TPSA (Å²): 12.9 computed here · PubChem 41.1
Formal charge: 0
XLogP3: 2 PubChem
Complexity: 105 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

C62.19%
H3.73%
N10.36%
S23.72%

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: 2.3 Crippen (Wildman and Crippen 1999)
log S (water solubility): -2.86 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 1.9 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 135.19
log P ≤ 5 (Crippen): 2.3
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: 1,775 company reports to ECHA. Source [4].

Acute toxicity
Harmful or irritant

H301+H311Toxic if swallowed or in contact with skin (10.2% of reports)
H301Toxic if swallowed (88.2% of reports)
H302Harmful if swallowed (11.8% of reports)
H311Toxic in contact with skin (88.3% of reports)
H319Causes serious eye irritation (88.3% of reports)
H332Harmful if inhaled (88.2% of reports)

Precautionary statements: P261, P262, P264, P264+P265, P270, P271, P280, P301+P316, P301+P317, P302+P352, P304+P340, P305+P351+P338, P316, P317, P321, P330, P337+P317, P361+P364, P405, P501

Incompatibilities

React WITH water, steam OR acids TO produce toxic & flammable vapors OF hydrogen sulfide. (sulfides)[2]
ON contact WITH ACID, ACID fumes, water OR steam, THEY WILL produce toxic & flammable vapors. (cyanides)[2]

Safety data sheets on the supplier’s page: Molport, Aladdin Scientific, Glentham Life Sciences Ltd..

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]EPA Chemical Data Reporting (CDR) · Public domain (US EPA) · via PubChem · retrieved 2026-10-14
[2]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[3]PAC Chemical Database, U.S. Department of Energy · Public domain (US DOE) · via PubChem · retrieved 2026-10-14
[4]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[5]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
[6]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[7]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[8]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[9]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
[10]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.