Formaldehyde
CH2O, 30.026 g/mol. Its structure, the values that were measured, the values that were calculated, and where each one came from.
Identifiers
- Molecular formula
- CH₂O
- Molecular weight
- 30.026 g/mol
- Exact mass
- 30.010565 g/mol
- IUPAC name
- formaldehyde
- C=O
- InChI=1S/CH2O/c1-2/h1H2
- WSFSSNUMVMOOMR-UHFFFAOYSA-N
Measured properties
Values somebody obtained from a sample and published. Where two sources report the same property they are both shown, in the units each used — a disagreement between them is information, and averaging it away would be inventing a number neither one gave.
- Boiling Point
- -6 °F at 760 mmHg (NIOSH, 2024)
- -3.1 °F at 760 mmHg ; commercial aqueous formaldehyde boils at 205 °F (EPA, 1998)
- Melting Point
- -134 °F (NIOSH, 2024)
- -134 °F for anhydrous form (EPA, 1998)
- Density
- 0.815 at -4 °F anhydrous form (EPA, 1998) - Less dense than water; will float
- 1.08 at 77 °F (NIOSH, 2024) - Denser than water; will sink
- Solubility
- Miscible (NIOSH, 2024)
- Miscible (NIOSH, 2024)
- Vapor Pressure
- greater than 1 atm (NIOSH, 2024)
- 10 mmHg at -126.4 °F for anhydrous form (EPA, 1998)
- LogP
- 0.35
- log Kow = 0.35
- Flash Point
- 140 °F for 40% solution (EPA, 1998)
- 185 °F (NIOSH, 2024)
- Viscosity
- 0.1421 cP at 25 °C
- Refractive Index
- Index of refraction: 1.3746 at 20 °C/D /Formaldehyde soln/
Calculated properties
Derived from the structure rather than from a sample. These are reproducible and they are not measurements: a calculated partition coefficient and a measured one can differ by a long way, and where both exist they are listed apart on purpose.
- Molecular weight
- 30.026 g/mol
- Exact mass
- 30.010564683 Da
- XLogP3
- 1.2
- Polar surface area
- 17.1 Ų
- Complexity
- 2
- H-bond donors
- 0
- H-bond acceptors
- 1
- logP
- -0.1849
- Topological polar surface area
- 17.07 Ų
- H-bond donors
- 0
- H-bond acceptors
- 1
- Rotatable bonds
- 0
- Molar refractivity
- 7.121 cm³/mol
- Fraction sp³ carbons
- 0
- QED drug-likeness
- 0.3606
What it is made of
Elements
Structure
- Heavy atoms, hydrogen excluded
- 2
- Total atoms, hydrogen included
- 4
- Rings
- 0
- Aromatic rings
- 0
- Stereocentres
- 0
- Formal charge
- 0
The molecule in three dimensions
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
Other names for it
The systematic name on this record is formaldehyde.
The sources also call it formalin, methanal, formol, Formic aldehyde, Methylene oxide, Oxomethane, Oxymethylene, Methyl aldehyde, Superlysoform, Lysoform, Fannoform.
Structurally related
Seen alongside it in reaction records
Molecules that appear in the same recorded reactions as Formaldehyde. 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-(2-Bromophenyl)cyclobutyl]-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline
used as a reactant
C₂₁H₂₄BrNO₂, 402.332 g/mol.
(+)-O,O'-dibenzoyltartaric acid
used as a reactant
C₁₈H₁₄O₈, 358.302 g/mol.
(-)-1-[1-(2-Bromophenyl)cyclobutyl]-6,7-dimethoxy-2-methyl-1,2,3,4-tetrahydroisoquinoline
formed as a product
C₂₂H₂₆BrNO₂, 416.359 g/mol.
1'-[(4-methylpiperazin-1-yl)methyl]spiro[furo[2,3-f][1,3]benzodioxole-7,3'-indol]-2'(1'H)-one
formed as a product
C₂₂H₂₃N₃O₄, 393.443 g/mol.
Where these values came from
chemistry engine
What this page does not claim
The identifiers are what the source record holds, copied rather than recomputed. Measured values are reported as their source gave them, units and all; calculated values are marked as calculated and are not measurements. Where a field is absent the page says so, because a blank cell reads as a zero and a guessed value reads as a fact.
Nothing here is a hazard assessment, a purity statement or advice about handling a sample. A flash point quoted from a safety database is a number somebody published, not a judgement by us about whether this molecule is safe for what you intend.