Oxalic Acid

A carboxylic acid, C2H2O4, 90.034 g/mol. Boiling point Sublimes, melting point 189.5 dec °C, as published.

verified recordOrganic — carboxylic acid6 measured properties

Identifiers

Molecular formula: C₂H₂O₄
Molecular weight: 90.034 g/mol
Exact mass: 89.995309 g/mol
IUPAC name: oxalic acid
SMILES: O=C(O)C(=O)O
InChI: InChI=1S/C2H2O4/c3-1(4)2(5)6/h(H,3,4)(H,5,6)
InChIKey: MUBZPKHOEPUJKR-UHFFFAOYSA-N

Open in ReactionLens Use in reaction prediction

Measured properties

Published measurements, each with its source. Two readings of one property are both shown, in the units each used.

Boiling Point: Sublimes (NIOSH, 2024)measured · CAMEO Chemicals; sublimesmeasured · Occupational Safety and Health Administration (OSHA)
Melting Point: 372 °F (Decomposes) (NTP, 1992)measured · CAMEO Chemicals; 189.5 dec °Cmeasured · DrugBank
Density: 1.9 at 59 °F (USCG, 1999) - Denser than water; will sinkmeasured · CAMEO Chemicals; 1.90 @ 17 DEG/4 °C, ALPHAmeasured · Hazardous Substances Data Bank (HSDB)
Solubility: 50 to 100 mg/mL at 75 °F (NTP, 1992)measured · CAMEO Chemicals; 220000 mg/L (at 25 °C)measured · DrugBank
Vapor Pressure: 0.001 mmHg at 68 °F (NTP, 1992)measured · CAMEO Chemicals; 0.000234 [mmHg]measured · Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
LogP: -0.81measured · ILO-WHO International Chemical Safety Cards (ICSCs); -0.81measured · SangsterLogP

Calculated properties

Derived from the structure, not from a sample; kept apart from the measurements above.

Molecular weight: 90.03 g/molcalculated · reference compound database; Average mass of one molecule, from reference compound database.
Exact mass: 89.99530854 Dacalculated · reference compound database; Mass of the most common isotopic form.
XLogP3: -0.3calculated · reference compound database; Estimated oil/water partition, computed by reference compound database.
Polar surface area: 74.6 Å²calculated · reference compound database; Polar surface area as computed by reference compound database.
Complexity: 71calculated · reference compound database; A rough measure of how intricate the structure is.
H-bond donors: 2calculated · reference compound database
H-bond acceptors: 4calculated · reference compound database
logP: -0.8444calculated · chemistry engine; Estimated preference for oil over water. Higher means more oil-like.
Topological polar surface area: 74.6 Å²calculated · chemistry engine; Surface area from polar atoms; relates to how easily a molecule crosses membranes.
H-bond donors: 2calculated · chemistry engine; Atoms that can donate a hydrogen bond.
H-bond acceptors: 2calculated · chemistry engine; Atoms that can accept a hydrogen bond.
Rotatable bonds: 0calculated · chemistry engine; Single bonds the molecule can freely twist around.
Molar refractivity: 15.2716 cm³/molcalculated · chemistry engine; Relates to the molecule's polarisability.
Fraction sp³ carbons: 0calculated · chemistry engine; Share of carbon atoms with tetrahedral bonding.
QED drug-likeness: 0.3799calculated · chemistry engine; Quantitative estimate of drug-likeness (0–1).

What it is made of

Elements

O Oxygen4 atoms · 71.1% by mass
C Carbon2 atoms · 26.7% by mass
H Hydrogen2 atoms · 2.2% by mass

Percentages are of the molecular weight above, worked out the same way the molar mass calculator does it.

Structure

Heavy atoms, hydrogen excluded: 6
Total atoms, hydrogen included: 8
Rings: 0
Aromatic rings: 0
Stereocentres: 0
Formal charge: 0

Functional groups

Carboxylic acid
A carbon double-bonded to oxygen and bonded to an –OH group; acidic.

Matched by structural pattern, not by a measurement.

The molecule in three dimensions

Rotate and inspect the atoms. Loaded only when you ask, so the page stays light.

The drawing above is a diagram of what is bonded to what. A molecule is not flat, and the model here is one low-energy shape generated from the connectivity — useful for seeing which groups can reach each other, and not a measured structure. A real sample is a population of conformations, interconverting.

Reactions it appears in

No documented reaction with a written procedure and a source involves Oxalic Acid yet.

Other names for it

The systematic name on this record is oxalic acid.

The sources also call it ethanedioic acid, Aktisal, Aquisal, Oxiric acid, Kyselina stavelova, Oxaalzuur, Oxalsaeure, Acidum oxalicum, Acide oxalique, Acido ossalico, Ethanedionic acid.

Structurally related

Nothing structurally close to Oxalic Acid has a page here yet.

Seen alongside it in reaction records

Molecules that appear in the same recorded reactions as Oxalic Acid. This says nothing about structure: most of them are the bases, solvents, ligands and catalysts the chemistry needed, and they are here because somebody put them in the same flask.

1,1'-Carbonyldiimidazole

used as a reactant

C₇H₆N₄O, 162.152 g/mol.

Where these values came from

reference compound database971
compound record
chemistry engine
structure perception

compound record.

What this page does not claim

Identifiers are copied from the source record, measured values are reported as published, and calculated values are marked as calculated. Nothing here is a hazard, purity or handling assessment — how the library is checked.