Citric acid
- Formula: C6H8O7
- Molecular weight: 192.1235
- IUPAC Standard InChI: InChI=1S/C6H8O7/c7-3(8)1-6(13,5(11)12)2-4(9)10/h13H,1-2H2,(H,7,8)(H,9,10)(H,11,12)
- IUPAC Standard InChIKey: KRKNYBCHXYNGOX-UHFFFAOYSA-N
- CAS Registry Number: 77-92-9
- Chemical structure:
This structure is also available as a 2d Mol file - Other names: 1,2,3-Propanetricarboxylic acid, 2-hydroxy-; Aciletten; Citretten; Citro; 2-Hydroxy-1,2,3-propanetricarboxylic acid; β-Hydroxytricarballylic acid; Anhydrous citric acid; Citric acid, anhydrous; Kyselina citronova; Kyselina 2-hydroxy-1,2,3-propantrikarbonova; 3-Carboxy-3-hydroxypentane-1,5-dioic acid; Chemfill; F 0001 (polycarboxylic acid); Hydrocerol A; NSC 30279; NSC 626579; K-Lyte DS (Salt/Mix); K-Lyte (Salt/Mix); Citraclean (Salt/Mix); K-Lyte/Cl (Salt/Mix)
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Condensed phase thermochemistry data
Go To: Top, Phase change data, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DH - Eugene S. Domalski and Elizabeth D. Hearing
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔfH°solid | -369.0 ± 1.1 | kcal/mol | Ccb | Wilhoit and Shiao, 1964 | Reanalyzed by Cox and Pilcher, 1970, Original value = -369.0 ± 1.1 kcal/mol; ALS |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔcH°solid | -468.6 ± 1.1 | kcal/mol | Ccb | Wilhoit and Shiao, 1964 | Reanalyzed by Cox and Pilcher, 1970, Original value = -469.5 ± 1.1 kcal/mol; Corresponding ΔfHºsolid = -368.97 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS |
| Quantity | Value | Units | Method | Reference | Comment |
| S°solid,1 bar | 60.25 | cal/mol*K | N/A | De Kruif, Van Miltenburg, et al., 1982 | DH |
Constant pressure heat capacity of solid
| Cp,solid (cal/mol*K) | Temperature (K) | Reference | Comment |
|---|---|---|---|
| 54.137 | 300. | De Kruif, Van Miltenburg, et al., 1982 | T = 90 to 330 K.; DH |
Phase change data
Go To: Top, Condensed phase thermochemistry data, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled by: Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| Tfus | 427.15 | K | N/A | Wilhoit and Shiao, 1964, 2 | Uncertainty assigned by TRC = 1.5 K |
References
Go To: Top, Condensed phase thermochemistry data, Phase change data, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Wilhoit and Shiao, 1964
Wilhoit, R.C.; Shiao, D.,
Thermochemistry of biologically important compounds. Heats of combustion of solid organic acids.,
J. Chem. Eng. Data, 1964, 9, 595-599. [all data]
Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G.,
Thermochemistry of Organic and Organometallic Compounds, Academic Press, New York, 1970, 1-636. [all data]
De Kruif, Van Miltenburg, et al., 1982
De Kruif, C.G.; Van Miltenburg, J.C.; Sprenkels, A.J.J.; Stevens, G.,
Thermodynamic properties of citric acid and the system citric acid-water,
Thermochim. Acta, 1982, 58, 341-354. [all data]
Wilhoit and Shiao, 1964, 2
Wilhoit, R.C.; Shiao, D.,
Thermochemistry of Biologically Important Compounds. Heats of Combustion of Solid Organic Acids,
J. Chem. Eng. Data, 1964, 9, 595. [all data]
Notes
Go To: Top, Condensed phase thermochemistry data, Phase change data, References
- Symbols used in this document:
Cp,solid Constant pressure heat capacity of solid S°solid,1 bar Entropy of solid at standard conditions (1 bar) Tfus Fusion (melting) point ΔcH°solid Enthalpy of combustion of solid at standard conditions ΔfH°solid Enthalpy of formation of solid at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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