Malonic acid (C3H4O4): structure, properties and hazards

Names and identifiers

IUPAC name: propanedioic acid
Synonyms: propanedioic acid, Dicarboxymethane, Carboxyacetic acid
+ 35 more
Methanedicarboxylic acid, malonate, Kyselina malonova, USAF EK-695, 1,3-Propanedioic acid, DTXSID7021659, 9KX7ZMG0MK, NSC-8124, DTXCID401659, CHEBI:30794, malonyl, disodium;malonate, RefChem:5980, 205-503-0, hydron;propanedioate, Dicarboxylic acid, Kyselina malonova [Czech], MFCD00002707, Propane-1,3-dioic acid, NSC 8124, Methanedicarbonic acid, AI3-15375, Malonicacid, alpha,omega-Dicarboxylic acid, NSC8124, 1,3-Propanoic acid, Thallium malonate, PROPANEDIOLIC ACID, METAHNEDICARBOXYLIC ACID, EINECS 205-503-0, UNII-9KX7ZMG0MK, BRN 1751370, H2malo, 2fah, Malonic acid-13C3
Molecular formula: C₃H₄O₄
Empirical formula: C₃H₄O₄
Molecular weight: 104.06 g/mol
Exact mass: 104.01096
CAS number: 141-82-2
PubChem CID: 867
Canonical SMILES: C(C(=O)O)C(=O)O
Isomeric SMILES: C(C(=O)O)C(=O)O
InChI: InChI=1S/C3H4O4/c4-2(5)1-3(6)7/h1H2,(H,4,5)(H,6,7)
InChIKey: OFOBLEOULBTSOW-UHFFFAOYSA-N
Molfile

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

Physical properties

TemperaturePressureDensity

Appearance: White crystals[4]
6 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– Malonic acid appears as white crystals or crystalline powder. Sublimes in vacuum. (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.
– Large Crystals; Liquid; Other Solid [2] EPA Chemical Data Reporting (CDR)
– WHITE CRYSTALS. [3] ILO-WHO International Chemical Safety Cards (ICSCs)
–shown White crystals [4] Hazardous Substances Data Bank (HSDB)cites Larranaga, M.D., Lewis, R.J. Sr., Lewis, R.A.; Hawley's Condensed Chemical Dictionary 16th Edition. John Wiley & Sons, Inc. Hoboken, NJ 2016., p. 859
– Crystalline powder [4] Hazardous Substances Data Bank (HSDB)cites NOAA; CAMEO Chemicals. Database of Hazardous Materials. Malonic Acid (141-82-2). Natl Ocean Atmos Admin, Off Resp Rest; NOAA Ocean Serv. Available from, as of July 16, 2018: https://cameochemicals.noaa.gov/
– Colorless hygroscopic solid which sublimes in vacuum [4] Hazardous Substances Data Bank (HSDB)cites Strittmatter H et al; Malonic Acid and Derivatives. Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (1999-2018). New York, NY: John Wiley & Sons. Online Posting Date: 15 April 2007
Melting point: 135.6 °C (276.1 °F, NTP 1992)[1]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source
135.6 °Cshown 276.1 °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.
135 to 137 °C 135-137 °C [4] Hazardous Substances Data Bank (HSDB)cites Sigma-Aldrich; Product Search Malonic acid (141-82-2). Available from, as of Oct 11, 2018: https://www.sigmaaldrich.com/united-states.html
Boiling point: 140 °C (284 °F) at 760 mmHg (decomposes) (NTP, 1992)[1]
Density: 1.63 @ 10°C[5]
3 values
3 of 3 sources agree on it (most common value).
Value As written Source
– 1.63 (NTP, 1992) - Denser than water [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.
– 1.6 g/cm³ [3] ILO-WHO International Chemical Safety Cards (ICSCs)
–shown 1.63 @ 10°C [5] PAC Chemical Database, U.S. Department of Energy
Solubility in water: Solubility in water, g/100ml at 20 °C: 7.3[3]
4 values
From ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative source here.
Value As written Source
– greater than or equal to 100 mg/mL at 72 °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.
– In water, 6.23X10+5 mg/L at 25 °C [4] Hazardous Substances Data Bank (HSDB)cites Yalkowsky, S.H., He, Yan, Jain, P. Handbook of Aqueous Solubility Data Second Edition. CRC Press, Boca Raton, FL 2010, p. 51
– In water, 7.66X10+5 mg/L at 20 °C (pH 1-10), EU Guideline Method A.6 (flask method) [4] Hazardous Substances Data Bank (HSDB)cites ECHA; Search for Chemicals. Malonic Acid (141-82-2) Registered Substances Dossier. European Chemical Agency. Available from, as of July 16, 2018: https://echa.europa.eu/
–shown Solubility in water, g/100ml at 20 °C: 7.3 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
log P: -0.91/-0.18 (calculated)[3]
2 values
Sources disagree; from ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative.
Value As written Source
– log Kow = -0.81 [4] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 5
–shown -0.91/-0.18 (calculated) [3] ILO-WHO International Chemical Safety Cards (ICSCs)
pKa: pKa1 = 2.8, pKa2 = 5.7 at 25 °C[4]
Vapor pressure: 2.7 × 10⁻⁶ mmHg at 23 °C[4]

Value	As written	Source
–	Malonic acid appears as white crystals or crystalline powder. Sublimes in vacuum. (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.
–	Large Crystals; Liquid; Other Solid	[2] EPA Chemical Data Reporting (CDR)
–	WHITE CRYSTALS.	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–shown	White crystals	[4] Hazardous Substances Data Bank (HSDB)cites Larranaga, M.D., Lewis, R.J. Sr., Lewis, R.A.; Hawley's Condensed Chemical Dictionary 16th Edition. John Wiley & Sons, Inc. Hoboken, NJ 2016., p. 859
–	Crystalline powder	[4] Hazardous Substances Data Bank (HSDB)cites NOAA; CAMEO Chemicals. Database of Hazardous Materials. Malonic Acid (141-82-2). Natl Ocean Atmos Admin, Off Resp Rest; NOAA Ocean Serv. Available from, as of July 16, 2018: https://cameochemicals.noaa.gov/
–	Colorless hygroscopic solid which sublimes in vacuum	[4] Hazardous Substances Data Bank (HSDB)cites Strittmatter H et al; Malonic Acid and Derivatives. Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (1999-2018). New York, NY: John Wiley & Sons. Online Posting Date: 15 April 2007

Value	As written	Source
135.6 °Cshown	276.1 °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.
135 to 137 °C	135-137 °C	[4] Hazardous Substances Data Bank (HSDB)cites Sigma-Aldrich; Product Search Malonic acid (141-82-2). Available from, as of Oct 11, 2018: https://www.sigmaaldrich.com/united-states.html

Value	As written	Source
–	1.63 (NTP, 1992) - Denser than water	[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.
–	1.6 g/cm³	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–shown	1.63 @ 10°C	[5] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
–	greater than or equal to 100 mg/mL at 72 °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.
–	In water, 6.23X10+5 mg/L at 25 °C	[4] Hazardous Substances Data Bank (HSDB)cites Yalkowsky, S.H., He, Yan, Jain, P. Handbook of Aqueous Solubility Data Second Edition. CRC Press, Boca Raton, FL 2010, p. 51
–	In water, 7.66X10+5 mg/L at 20 °C (pH 1-10), EU Guideline Method A.6 (flask method)	[4] Hazardous Substances Data Bank (HSDB)cites ECHA; Search for Chemicals. Malonic Acid (141-82-2) Registered Substances Dossier. European Chemical Agency. Available from, as of July 16, 2018: https://echa.europa.eu/
–shown	Solubility in water, g/100ml at 20 °C: 7.3	[3] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
–	log Kow = -0.81	[4] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 5
–shown	-0.91/-0.18 (calculated)	[3] 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: 7
Rings: 0
Aromatic rings: 0
Fraction sp³ carbons (Fsp3): 0.33
H-bond donors: 2
H-bond acceptors: 2 computed here · PubChem 4
Rotatable bonds: 2
TPSA (Å²): 74.6
Formal charge: 0
XLogP3: -0.8 PubChem
Complexity: 83 PubChem
Stereocenters: None
Double-bond geometry: None specified
Point group: C2 of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

C34.63%
H3.87%
O61.50%

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: -0.45 Crippen (Wildman and Crippen 1999)
log S (water solubility): -0.07 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 2.05 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 104.06
log P ≤ 5 (Crippen): -0.45
H-bond donors ≤ 5: 2
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: 443 company reports to ECHA. Source [6].

Corrosive
Harmful or irritant

H302Harmful if swallowed (47.2% of reports)
H315Causes skin irritation (28.2% of reports)
H318Causes serious eye damage (49.7% of reports)
H319Causes serious eye irritation (49% of reports)
H335May cause respiratory irritation (11.5% of reports)

Precautionary statements: P261, P264, P264+P265, P270, P271, P280, P301+P317, P302+P352, P304+P340, P305+P351+P338, P305+P354+P338, P317, P319, P321, P330, P332+P317, P337+P317, P362+P364, P403+P233, P405, P501

View all classifications (3)

[6] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for 1.4% (6 of 443) of reports.
[6] European Chemicals Agency (ECHA) · 443 reports · DangerH302, H315, H318, H319, H335
[4] Hazardous Substances Data Bank (HSDB) · DangerH302, H318

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]
Fresh air, rest. Refer for medical attention.[3]
Remove contaminated clothes. Rinse skin with plenty of water or shower.[3]
First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.[3]

Storage

Separated from bases and strong oxidants.[3]
Keep container tightly closed in a dry and well-ventilated place. Keep in a dry place.[4]

Incompatibilities

Incompatible materials: Bases, Oxidizing agents, Reducing agents[4]

Safety data sheets on the supplier’s page: Cooke Chemical Co., Ltd, Sigma-Aldrich, BenchChem.

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]EPA Chemical Data Reporting (CDR) · Public domain (US EPA) · via PubChem · retrieved 2026-10-14
[3]ILO-WHO International Chemical Safety Cards (ICSCs) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[4]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[5]PAC Chemical Database, U.S. Department of Energy · Public domain (US DOE) · via PubChem · retrieved 2026-10-14
[6]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[7]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
[8]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[9]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[10]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
[11]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[12]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%.