2-Pyridone

2-Pyridone
Names
	Preferred IUPAC name Pyridin-2(1H)-one
	Other names 2(1H)-Pyridinone; 2(1H)-Pyridone; 1H-Pyridine-2-one; 2-Pyridone; 1,2-Dihydro-2-oxopyridine; 1H-2-Pyridone; 2-Oxopyridone; 2-Pyridinol; 2-Hydroxypyridine
Identifiers
CAS Number	142-08-5 ;
3D model (JSmol)	lactim: Interactive image; lactam: Interactive image;
ChEBI	CHEBI:16540 ;
ChEMBL	ChEMBL662 ;
ChemSpider	8537 ;
ECHA InfoCard	100.005.019
EC Number	205-520-3;
KEGG	C02502;
PubChem CID	8871;
RTECS number	UV1144050;
UNII	6770O3A2I5 ;
CompTox Dashboard (EPA)	DTXSID2051716 ;
	InChI InChI=1S/C5H5NO/c7-5-3-1-2-4-6-5/h1-4H,(H,6,7) Key: UBQKCCHYAOITMY-UHFFFAOYSA-N ; InChI=1/C5H5NO/c7-5-2-1-3-6-4-5/h1-4,7H Key: GRFNBEZIAWKNCO-UHFFFAOYAT; InChI=1/C5H5NO/c7-5-3-1-2-4-6-5/h1-4H,(H,6,7) Key: UBQKCCHYAOITMY-UHFFFAOYAK;
	SMILES lactim: Oc1ccccn1; lactam: C1=CC=CNC(=O)1;
Properties
Chemical formula	C5H5NO
Molar mass	95.101 g·mol−1
Appearance	Colourless crystalline solid
Density	1.39 g/cm3
Melting point	107.8 °C (226.0 °F; 380.9 K)
Boiling point	280 °C (536 °F; 553 K) decomp.
Solubility in other solvents	Soluble in water,; methanol, acetone
Acidity (pKa)	11.65
UV-vis (λmax)	293 nm (ε 5900, H2O soln)
Structure
Crystal structure	Orthorhombic
Molecular shape	planar
Dipole moment	4.26 D
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	irritating
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H301, H315, H319, H335
Precautionary statements	P261, P264, P270, P271, P280, P301+P310, P302+P352, P304+P340, P305+P351+P338, P312, P321, P330, P332+P313, P337+P313, P362, P403+P233, P405, P501
NFPA 704 (fire diamond)	2 1
Flash point	210 °C (410 °F; 483 K)
Related compounds
Other anions	2-Pyridinolate
Other cations	2-Hydroxypyridinium-ion
Related functional groups	alcohol, lactam, lactim,; pyridine, ketone
Related compounds	pyridine, thymine, cytosine,; uracil, benzene
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

2-Pyridone is an organic compound with the formula C
₅H
₄NH(O). It is a colourless solid. It is well known to form hydrogen bonded dimers and it is also a classic case of a compound that exists as tautomers.