Names
Preferred IUPAC name: 2-Hydroxypropane-1,2,3-tricarboxylic acid
Other names
Citric acid
Identifiers
CAS Number: 77-92-9
JSmol: Interactive image
ChEBI: CHEBI:30769
ChEMBL: ChEMBL1261
ChemSpider: 305
DrugBank: DB04272
ECHA InfoCard: 100.000.973
EC Number: 201-069-1
E number: (antioxidants, …)
IUPHAR/BPS: 2478
KEGG: D00037
PubChem: 311
RTECS number: GE7350000
UNII: XF417D3PSL
Properties
Chemical formula: C6H8O7
Molar mass: 192.12 g·mol
Appearance: crystalline white solid
Odor: odorless
Density: 1.665 g/cm (anhydrous)
1.542 g/cm (18 °C, monohydrate)33
Melting point: 156 °C (313 °F; 429 K)
Boiling point: 310 °C (590 °F; 583 K) decomposes from 175 °C
Solubility in water: 117.43 g/100 mL (10 °C)
147.76 g/100 mL (20 °C)
180.89 g/100 mL (30 °C)
220.19 g/100 mL (40 °C)
382.48 g/100 mL (80 °C)
547.79 g/100 mL (100 °C)
Solubility: alcohol
Solubility: 62 g/100 g (25 °C)
Solubility: 4.41 g/100 g (25 °C)
Solubility: 1.05 g/100 g (25 °C)
Solubility: 35.9 g/100 g (25 °C)
log : −1.64
K: K
Refractive index: 1.493–1.509 (20 °C)
1.46 (150 °C)
Viscosity: 6.5 cP (50% aq. sol.)
Structure
Crystal structure: Monoclinic
Thermochemistry
Specific
heat capacity: 226.51 J/(mol·K) (26.85 °C)
Std molar
entropy: 252.1 J/(mol·K)
Std enthalpy of
formation: −1548.8 kJ/mol
Std enthalpy of
combustion: −1960.6 kJ/mol
−1972.34 kJ/mol (monohydrate)
Pharmacology
ATC code: WHOA09AB04
Hazards
hazards: skin and eye irritant
Safety data sheet: HMDB
GHS pictograms:
GHS signal word: Warning
GHS hazard statements: H319
GHS precautionary statements: P305+351+338
NFPA 704:
Flash point: 155 °C (311 °F; 428 K)
Autoignition
temperature: 345 °C (653 °F; 618 K)
Explosive limits: 8%
LD
median dose: 3000 mg/kg (rats, oral)
Except where otherwise noted, data are given for materials in their(at 25 °C [77 °F], 100 kPa).Except where otherwise noted, data are given for materials in their(at 25 °C [77 °F], 100 kPa).
Infobox references