Formaldehyde
Formaldehyde (/fɔːrˈmældɪhaɪd/ ⓘ for-MAL-di-hide, US also /fər-/ ⓘ fər-) (systematic name methanal) is an organic compound with the formula CH2O and structure H−CHO. The compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde. It is stored as aqueous solutions (formalin), which consists mainly of the hydrate CH2(OH)2. It is the simplest of the aldehydes (R−CHO). As a precursor to many other materials and chemical compounds, in 2006 the global production of formaldehyde was estimated at 12 million tons per year. It is mainly used in the production of industrial resins, e.g., for particle board and coatings. Small amounts also occur naturally.
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| Names | |||
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| Preferred IUPAC name
Formaldehyde | |||
| Systematic IUPAC name
Methanal | |||
| Other names
Methyl aldehyde Methylene glycol (diol forms in aqueous solution) Methylene oxide Formalin (aqueous solution) Formol Carbonyl hydride Methanone Oxomethane | |||
| Identifiers | |||
3D model (JSmol) |
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| 3DMet | |||
| 1209228 | |||
| ChEBI | |||
| ChEMBL | |||
| ChemSpider | |||
| DrugBank | |||
| ECHA InfoCard | 100.000.002 | ||
| EC Number |
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| E number | E240 (preservatives) | ||
| 445 | |||
| KEGG | |||
| MeSH | Formaldehyde | ||
PubChem CID |
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| RTECS number |
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| UNII | |||
| UN number | 2209 | ||
CompTox Dashboard (EPA) |
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| Properties | |||
| CH2O | |||
| Molar mass | 30.026 g·mol−1 | ||
| Appearance | Colorless gas | ||
| Density | 0.8153 g/cm3 (−20 °C) (liquid) | ||
| Melting point | −92 °C (−134 °F; 181 K) | ||
| Boiling point | −19 °C (−2 °F; 254 K) | ||
| 400 g/L | |||
| log P | 0.350 | ||
| Vapor pressure | > 1 atm | ||
| Acidity (pKa) | 13.27 (hydrate) | ||
| −18.6·10−6 cm3/mol | |||
| 2.330 D | |||
| Structure | |||
| C2v | |||
| Trigonal planar | |||
| Thermochemistry | |||
Heat capacity (C) |
35.387 J·mol−1·K−1 | ||
Std molar entropy (S⦵298) |
218.760 J·mol−1·K−1 | ||
Std enthalpy of formation (ΔfH⦵298) |
−108.700 kJ·mol−1 | ||
Gibbs free energy (ΔfG⦵) |
−102.667 kJ·mol−1 | ||
Std enthalpy of combustion (ΔcH⦵298) |
571 kJ·mol−1 | ||
| Pharmacology | |||
| QP53AX19 (WHO) | |||
| Hazards | |||
| GHS labelling: | |||
| Danger | |||
| H301, H311, H314, H317, H331, H335, H341, H350, H370 | |||
| P201, P280, P303+P361+P353, P304+P340+P310, P305+P351+P338, P308+P310 | |||
| NFPA 704 (fire diamond) | |||
| Flash point | 64 °C (147 °F; 337 K) | ||
| 430 °C (806 °F; 703 K) | |||
| Explosive limits | 7–73% | ||
| Lethal dose or concentration (LD, LC): | |||
LD50 (median dose) |
100 mg/kg (oral, rat) | ||
LC50 (median concentration) |
333 ppm (mouse, 2 h) 815 ppm (rat, 30 min) | ||
LCLo (lowest published) |
333 ppm (cat, 2 h) | ||
| NIOSH (US health exposure limits): | |||
PEL (Permissible) |
TWA 0.75 ppm ST 2 ppm (as formaldehyde and formalin) | ||
REL (Recommended) |
Ca TWA 0.016 ppm C 0.1 ppm [15-minute] | ||
IDLH (Immediate danger) |
Ca [20 ppm] | ||
| Safety data sheet (SDS) | MSDS(Archived) | ||
| Related compounds | |||
Related aldehydes |
Acetaldehyde Butyraldehyde | ||
Related compounds |
Methanol Formic acid | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references | |||
Formaldehyde is classified as a carcinogen and can cause respiratory and skin irritation upon exposure.