CH₂O
Compound · Organic
Formaldehyde
甲醛
Formaldehyde (甲醛), formula CH₂O, is a organic with a molar mass of 30.03 g/mol (CAS 50-00-0). Colourless pungent gas; a 37% solution is called formalin; extremely soluble in water.
Key facts
| Molar mass | 30.03 g/mol |
|---|---|
| Category | Organic |
| State at 25°C | Gas |
| CAS | 50-00-0 |
Structure
H₂C=O
Simplest aldehyde; trigonal planar
Physical properties
| Appearance | Colourless pungent gas; a 37% solution is called formalin |
|---|---|
| Melting point | −92 °C |
| Boiling point | −19 °C |
| Density | 1.09 g/L (气体) |
| Solubility | Extremely soluble in water |
Key reactions
CH₂O + O₂ →(点燃) CO₂ + H₂O
Combustible; complete combustion
2CH₂O + O₂ →(催化) 2HCOOH
Oxidised to formic acid
Main uses
- Making phenolic/urea resins and adhesives
- Biological specimen preservation (formalin)
- Disinfection and sterilisation
Hazard
HighToxic, strongly irritating and classified as a carcinogen
Constituent elements
Data sources
Molar mass is computed from IUPAC (CIAAW) standard atomic weights; formula, properties and reactions can be verified on PubChem, NIST and Wikipedia. The CAS number is the substance's unique registry identifier. Educational reference only.