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Pyridine

Heterocyclic aromatic organic compoundNames Preferred IUPAC namePyridineSystematic IUPAC nameAzabenzeneOther names AzineAzinineIdentifiers CAS Number110-86-13D model (JSmol)Interactive imageChEBICHEBI:16227ChEMBLChEMBL266158ChemSpider1020ECHA InfoCard100.003.464EC Number203-809-9KEGGC00747PubChemCID1049UNIINH9L3PP67SCompTox Dashboard(EPA)DTXSID9021924InChIInChI=1S/C5H5N/c1-2-4-6-5-3-1/h1-5HKey: JUJWROOIHBZHMG-UHFFFAOYSA-NInChI=1/C5H5N/c1-2-4-6-5-3-1/h1-5HKey: JUJWROOIHBZHMG-UHFFFAOYAYSMILESc1ccncc1Properties Chemical formulaC5H5NMolar mass79.102 g·mol Appearance Colorless liquid OdorNauseating, fish-like Density0.9819 g/mL (20 °C) Melting point−41.63 °C (−42.93 °F; 231.52 K) Boiling point115.2 °C (239.4 °F; 388.3 K) Solubility in waterMiscible log P0.65 Vapor pressure16 mmHg (20 °C) Acidity (pKa) 5.23 (pyridinium) Conjugate acidPyridiniumMagnetic susceptibility (χ)−48.7·10 cm/mol Thermal conductivity0.166 W/(m·K) Refractive index (nD)1.5095 (20 °C) Viscosity0.879 cP (25 °C) Dipole moment2.215 D Thermochemistry Heat capacity(C)132.7 J/(mol·K) Std enthalpy offormation(ΔfH298)100.2 kJ/mol Std enthalpy ofcombustion(ΔcH298)−2.782 MJ/mol Hazards Occupational safety and health (OHS/OSH): Main hazardsLow to moderate hazard GHS labelling: PictogramsSignal wordDangerHazard statementsH225, H302, H312, H315, H319, H332Precautionary statementsP210, P280, P301+P312, P303+P361+P353, P304+P340+P312, P305+P351+P338NFPA 704 (fire diamond) 230Flash point20 °C (68 °F; 293 K) Autoignitiontemperature482 °C (900 °F; 755 K) Explosive limits1.8–12.4% Threshold limit value (TLV)5 ppm (TWA) Lethal dose or concentration (LD, LC): LD50 (median dose)891 mg/kg (rat, oral)1500 mg/kg (mouse, oral)1580 mg/kg (rat, oral) LC50 (median concentration)9000 ppm (rat, 1 hr) NIOSH (US health exposure limits): PEL (Permissible)TWA 5 ppm (15 mg/m) REL (Recommended)TWA 5 ppm (15 mg/m) IDLH (Immediate danger)1000 ppm Related compounds Related aminesPicolineQuinolineRelated compoundsAnilinePyrimidinePiperidineSupplementary data page Pyridine (data page)Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).N verify ( ?)

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