Cobalt(II) chloride

Athanor · official

Cl₂Co · 129.84 g/mol

IUPAC name: cobalt(2+) dichloride

Also called humidity indicator

Inorganic

Open in Athanor

Drawn from its SMILES with RDKit

DangerHarmful if swallowed · May cause an allergic skin reaction · May cause allergy or asthma symptoms or breathing difficulties if inhaled · Suspected of causing genetic defects · May cause cancer by inhalation · Very toxic to aquatic life · Very toxic to aquatic life with long lasting effects

Names and identifiers

IUPAC name: cobalt(2+) dichloride
Synonyms: humidity indicator, Dichlorocobalt, Cobalt dichloride
+ 36 more
Cobalt muriate, Cobaltous dichloride, Cobaltous chloride anhydrous, Cobalt(2+) chloride, Kobalt chlorid, Cobaltum muriaticum, EVS87XF13W, CHEBI:35696, Cobalt dichloride (cocl2), NSC-51149, CoCl(2), RefChem:54867, lambda2-cobalt(2+) ion dichloride, Technetium Tc-99m Exametazime and Cobaltous Chloride, 231-589-4, Cobalt chloride (cocl2), Cobalt(II)chloride, Cobaltous Chloride, COCl2, cobalt(2+);dichloride, Cobalt(II) chloride anhydrous, cobalt(2+) dichloride, Cl2Co, Kobalt chlorid (German), Kobaltdichlorid, CCRIS 4224, DTXSID9040180, HSDB 1000, EINECS 231-589-4, Kobalt(II)-chlorid, NSC 51149, Epitope ID:115003, UNII-EVS87XF13W, SCHEMBL15588, COBALTOUS CHLORIDE [MI], COBALT CHLORIDE [MART.]
Molecular formula: Cl₂Co
Empirical formula: Cl₂Co
Molecular weight: 129.84 g/mol
Exact mass: 128.87090
CAS number: 7646-79-9
PubChem CID: 3032536
Canonical SMILES: [Cl-].[Cl-].[Co+2]
Isomeric SMILES: [Cl-].[Cl-].[Co+2]
InChI: InChI=1S/2ClH.Co/h2*1H;/q;;+2/p-2
InChIKey: GVPFVAHMJGGAJG-UHFFFAOYSA-L
Molfile

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

Physical properties

TemperaturePressureDensity

Appearance: Cobalt chloride is a pink to red solid with a slight sharp odor. Sinks and mixes with water. Pale blue leaflets, turns pink upon exposure to moist air.[1]
2 values
From CAMEO Chemicals, the most authoritative source here.
Value As written Source
–shown Cobalt chloride is a pink to red solid with a slight sharp odor. Sinks and mixes with water. Pale blue leaflets, turns pink upon exposure to moist air. [1] CAMEO Chemicals
– Liquid [2] EPA Chemical Data Reporting (CDR)
Odor: Slight sharp odor[3]
Melting point: 737 °C[4]
2 values
Sources disagree; from PAC Chemical Database, U.S. Department of Energy, the most authoritative.
Value As written Source
86 °C 187 °F (USCG, 1999) [1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
737 °Cshown 737 °C [4] PAC Chemical Database, U.S. Department of Energy
Boiling point: 1049 °C @760 [mmHg][4]
Density: 3.348 @25 °C[4]
2 values
Sources disagree; from PAC Chemical Database, U.S. Department of Energy, the most authoritative.
Value As written Source
– 1.924 at 68 °F (USCG, 1999) - Denser than water [1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
–shown 3.348 @25 °C [4] PAC Chemical Database, U.S. Department of Energy
Solubility in water: In water, 1.16 kg/L at 0 °C[3]
3 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– 53.420 lb/100 lb water at 70 °F [3] Hazardous Substances Data Bank (HSDB)cites NOAA; CAMEO Chemicals. Database of Hazardous Materials. Cobalt Chloride (7646-79-9). Natl Ocean Atmos Admin, Off Resp Rest; NOAA Ocean Serv. Available from, as of Jan 19, 2017: https://cameochemicals.noaa.gov/
–shown In water, 1.16 kg/L at 0 °C [3] Hazardous Substances Data Bank (HSDB)cites Ashford, R.D. Ashford's Dictionary of Industrial Chemicals. London, England: Wavelength Publications Ltd., 1994., p. 230
– For more Solubility (Complete) data for Cobaltous chloride (6 total), please visit the HSDB record page. [3] Hazardous Substances Data Bank (HSDB)
Vapor pressure: 75 [mmHg] @818 °C[4]

Value	As written	Source
–shown	Cobalt chloride is a pink to red solid with a slight sharp odor. Sinks and mixes with water. Pale blue leaflets, turns pink upon exposure to moist air.	[1] CAMEO Chemicals
–	Liquid	[2] EPA Chemical Data Reporting (CDR)

Value	As written	Source
86 °C	187 °F (USCG, 1999)	[1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
737 °Cshown	737 °C	[4] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
–	1.924 at 68 °F (USCG, 1999) - Denser than water	[1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
–shown	3.348 @25 °C	[4] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
–	53.420 lb/100 lb water at 70 °F	[3] Hazardous Substances Data Bank (HSDB)cites NOAA; CAMEO Chemicals. Database of Hazardous Materials. Cobalt Chloride (7646-79-9). Natl Ocean Atmos Admin, Off Resp Rest; NOAA Ocean Serv. Available from, as of Jan 19, 2017: https://cameochemicals.noaa.gov/
–shown	In water, 1.16 kg/L at 0 °C	[3] Hazardous Substances Data Bank (HSDB)cites Ashford, R.D. Ashford's Dictionary of Industrial Chemicals. London, England: Wavelength Publications Ltd., 1994., p. 230
–	For more Solubility (Complete) data for Cobaltous chloride (6 total), please visit the HSDB record page.	[3] Hazardous Substances Data Bank (HSDB)

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: 3
Rings: 0
Aromatic rings: 0
Fraction sp³ carbons (Fsp3): 0
H-bond donors: 0
H-bond acceptors: 0 computed here · PubChem 2
Rotatable bonds: 0
TPSA (Å²): 0
Formal charge: 0
Complexity: 0 PubChem
Stereocenters: None
Double-bond geometry: None specified
Point group: Kh of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

Cl54.61%
Co45.39%

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: -5.99 Crippen (Wildman and Crippen 1999)
log S (water solubility): 3.13 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 7.69 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 129.84
log P ≤ 5 (Crippen): -5.99
H-bond donors ≤ 5: 0
H-bond acceptors ≤ 10: 0

Passes all four rules.

Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.

Safety

Danger

Harmonized EU classification (CLP Annex VI). Source [5].

Harmful or irritant
Health hazard
Environmental hazard

H302Harmful if swallowed
H317May cause an allergic skin reaction
H334May cause allergy or asthma symptoms or breathing difficulties if inhaled
H341Suspected of causing genetic defects
H350iMay cause cancer by inhalation
H400Very toxic to aquatic life
H410Very toxic to aquatic life with long lasting effects

Precautionary statements: P203, P233, P260, P261, P264, P270, P271, P272, P273, P280, P284, P301+P317, P302+P352, P304+P340, P318, P321, P330, P333+P317, P342+P316, P362+P364, P391, P403, P405, P501

View all classifications (3)

[5] Regulation (EC) No 1272/2008 of the European Parliament and of the Council · DangerH302, H317, H334, H341, H350i, H400, H410
[6] European Chemicals Agency (ECHA) · 376 reports · DangerH302, H317, H318, H334, H341, H350, H350i, H360, H360Fd, H400, H410
[3] Hazardous Substances Data Bank (HSDB) · DangerH302, H317, H318, H334, H341, H350, H360, H400, H410

First aid

Inhalation: Move victim to fresh air; if breathing has stopped, begin artificial respiration and call a doctor. Ingestion: Give large amount of water; induce vomiting. Eyes: Flush with water at least 15 min.; consult physician if irritation persists. Skin: Flush with water. (USCG, 1999)[1]

Storage

Keep container tightly closed in a dry and well-ventilated place. ... Moisture sensitive. Handle and store under inert gas. Hygroscopic. ... Storage class (TRGS 510): Non-combustible, acute toxic Cat.3 / toxic hazardous materials or hazardous materials causing chronic effects.[3]
Dry.[3]
Store in airtight containers. (hexahydrate)[3]

Incompatibilities

Incompatible materials: Oxidizing agents, alkali metals.[3]
Mixtures of potassium with metal halides are sensitive to mechanical shock, and the ensuing explosions have been graded. Very violent explosions occurred with ... Cobalt(II) chloride ... .[3]
Sodium dispersions will reduce many metal halides exothermically. ... Cobalt chloride ... (requires) higher temp to initiate the reaction, the exotherm with cobalt chloride incr the temp from 325 to 375 °C and causing evaporation of most of the dispersing oil. ... Very violent explosions occurred with ... Cobalt(II) chloride ... .[3]
A very violent explosion results when a mixture of sodium and ... (cobaltous chloride) is struck with a hammer ... .[3]

Safety data sheets on the supplier’s page: Thermo Fisher Scientific, Smolecule, AEZ Kimya.

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

Spectra

RamanSpectraBase (Bio-Rad FTS 175C with Raman accessory · FT-Raman)

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]EPA Chemical Data Reporting (CDR) · Public domain (US EPA) · via PubChem · retrieved 2026-10-14
[3]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[4]PAC Chemical Database, U.S. Department of Energy · Public domain (US DOE) · via PubChem · retrieved 2026-10-14
[5]Regulation (EC) No 1272/2008 of the European Parliament and of the Council · EU reuse policy, CC BY 4.0 · via PubChem · retrieved 2026-10-14
[6]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[7]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.