Formic acid

Formula: CH₂O₂
Molecular weight: 46.0254
IUPAC Standard InChI: InChI=1S/CH2O2/c2-1-3/h1H,(H,2,3)
IUPAC Standard InChIKey: BDAGIHXWWSANSR-UHFFFAOYSA-N
CAS Registry Number: 64-18-6
Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
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Other names: Methanoic acid; Aminic acid; Bilorin; Collo-Bueglatt; Collo-Didax; Formisoton; Formylic acid; Hydrogen carboxylic acid; Myrmicyl; HCOOH; Acide formique; Acido formico; Ameisensaeure; Kwas metaniowy; Kyselina mravenci; Mierenzuur; Rcra waste number U123; UN 1779; Formira; Add-F; Amasil
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Gas phase thermochemistry data

Go To: Top, Condensed phase thermochemistry data, Phase change data, References, Notes

Data compiled as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DRB - Donald R. Burgess, Jr.
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	-378.6	kJ/mol	Cm	Guthrie, 1974	Heat of hydrolysis; ALS
Δ_fH°_gas	-379.0	kJ/mol	N/A	Lebedeva, 1964	Value computed using Δ_fH_liquid° value of -425.5±0.3 kj/mol from Lebedeva, 1964 and Δ_vapH° value of 46.5 kj/mol from Guthrie, 1974.; DRB
Δ_fH°_gas	-379.2 ± 0.6	kJ/mol	Ccb	Lebedeva, 1964	Value computed using Δ_fH_liquid° from Lebedeva, 1964 and Δ_vapH° value of 46.3 kJ/mol from Konicek and Wadso, 1970.; DRB
Δ_fH°_gas	-378.3	kJ/mol	N/A	Sinke, 1959	Value computed using Δ_fH_liquid° value of -424.8±0.3 kj/mol from Sinke, 1959 and Δ_vapH° value of 46.5 kj/mol from Guthrie, 1974.; DRB
Δ_fH°_gas	-378.5 ± 0.6	kJ/mol	Ccb	Sinke, 1959	Value computed using Δ_fH_liquid° from Sinke, 1959 and Δ_vapH° value of 46.3 kJ/mol from Konicek and Wadso, 1970.; DRB
Quantity	Value	Units	Method	Reference	Comment
S°_gas	248.70 ± 0.42	J/mol*K	N/A	Millikan R.C., 1957	Other third-law S(298.15 K) value is 248.11(1.26) J/mol*K [ Halford J.O., 1942, Millikan R.C., 1957]. Please also see Waring W., 1952.; GT

Constant pressure heat capacity of gas

C_p,gas (J/mol*K)	Temperature (K)	Reference	Comment
33.26	50.	Chao J., 1986	p=1 bar. Selected entropies and heat capacities are in close agreement with statistically calculated values [ Fukushima K., 1971] and value of S(298.15 K) calculated by ab initio method [ East A.L.L., 1997]. Maximum discrepancies with other statistical calculations [ Waring W., 1952, Green J.H.S., 1961, Gurvich, Veyts, et al., 1989] amount to 1.1-3.9 J/molK for S(T) and 3.0-5.9 J/molK for Cp(T). Please also see Chao J., 1978.; GT
33.44	100.
34.91	150.
37.83	200.
43.54	273.15
45.68 ± 0.07	298.15
45.84	300.
54.52	400.
62.63	500.
69.81	600.
76.04	700.
81.34	800.
85.77	900.
89.40	1000.
92.33	1100.
94.65	1200.
96.48	1300.
97.91	1400.
99.02	1500.

Condensed phase thermochemistry data

Go To: Top, Gas phase thermochemistry data, Phase change data, References, Notes

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
Δ_fH°_liquid	-425.09	kJ/mol	Cm	Guthrie, 1974	Heat of hydrolysis; ALS
Δ_fH°_liquid	-425.5 ± 0.3	kJ/mol	Ccb	Lebedeva, 1964	ALS
Δ_fH°_liquid	-424.8 ± 0.3	kJ/mol	Ccb	Sinke, 1959	ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_liquid	-253.8 ± 0.3	kJ/mol	Ccb	Lebedeva, 1964	Corresponding Δ_fHº_liquid = -425.51 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Δ_cH°_liquid	-254.6 ± 0.3	kJ/mol	Ccb	Sinke, 1959	Corresponding Δ_fHº_liquid = -424.72 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity	Value	Units	Method	Reference	Comment
S°_liquid	131.84	J/mol*K	N/A	Stout and Fisher, 1941	Includes 2.89 J/mol*K for zero-point entropy.; DH
S°_liquid	128.4	J/mol*K	N/A	Parks, Kelley, et al., 1929	Extrapolation below 90 K, 29.7 J/mol*K. Revision of previous data.; DH
S°_liquid	143.1	J/mol*K	N/A	Gibson, Latimer, et al., 1920	Used Berthelot's value, 10125 J/mol for H fusion. Extrapolation below 70 K, no details.; DH

Constant pressure heat capacity of liquid

C_p,liquid (J/mol*K)	Temperature (K)	Reference	Comment
99.04	298.15	Stout and Fisher, 1941	T = 15 to 300 K.; DH
98.10	298.15	Glagoleva and Chervov, 1936	Temperature range: 298.15, 333.15, 353.15 K.; DH
100.0	290.	Radulescu and Jula, 1934	DH
98.3	291.5	Gibson, Latimer, et al., 1920	T = 71 to 292 K. Value is unsmoothed experimental datum.; DH
95.4	298.	von Reis, 1881	T = 291 to 385 K.; DH

Phase change data

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, References, Notes

Data compiled as indicated in comments:
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
AC - William E. Acree, Jr., James S. Chickos
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
T_boil	373.9 ± 0.5	K	AVG	N/A	Average of 25 out of 30 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
T_fus	281.5 ± 0.6	K	AVG	N/A	Average of 9 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
T_triple	281.45	K	N/A	Wilhoit, Chao, et al., 1985	Uncertainty assigned by TRC = 0.1 K; TRC
T_triple	281.40	K	N/A	Stout and Fisher, 1941, 2	Uncertainty assigned by TRC = 0.06 K; TRC
Quantity	Value	Units	Method	Reference	Comment
P_triple	0.0236	bar	N/A	Taylor and Bruton, 1952	Uncertainty assigned by TRC = 0.000067 bar; TRC
Quantity	Value	Units	Method	Reference	Comment
T_c	577.	K	N/A	Anselme and Teja, 1990	Uncertainty assigned by TRC = 30. K; Tc > 577 K, which was observed with decomposition; TRC
T_c	588.	K	N/A	Ambrose and Ghiassee, 1987	Uncertainty assigned by TRC = 10. K; TRC
T_c	580.	K	N/A	Majer and Svoboda, 1985
Quantity	Value	Units	Method	Reference	Comment
Δ_vapH°	46.3	kJ/mol	N/A	Majer and Svoboda, 1985
Δ_vapH°	36.0	kJ/mol	A	Stephenson and Malanowski, 1987	Based on data from 283. to 384. K.; AC
Δ_vapH°	46.3 ± 0.5	kJ/mol	C	Konicek and Wadso, 1970	ALS
Δ_vapH°	46.3 ± 0.5	kJ/mol	C	Konicek, Wadsö, et al., 1970	AC
Δ_vapH°	19.9	kJ/mol	N/A	Stout and Fisher, 1941, 3	AC

Enthalpy of vaporization

Δ_vapH (kJ/mol)	Temperature (K)	Method	Reference	Comment
22.69	373.8	N/A	Majer and Svoboda, 1985
35.2	315.	EB	Ambrose and Ghiassee, 1987, 2	Based on data from 300. to 392. K.; AC
35.2	325.	N/A	Dreisbach and Shrader, 1949	Based on data from 310. to 374. K. See also Dreisbach and Martin, 1949.; AC
29.6	303.	N/A	Campbell and Campbell, 1934	AC
20.3	315.	N/A	Coolidge, 1930	Based on data from 273. to 373. K.; AC
20.9	338.	N/A	Coolidge, 1930	Based on data from 273. to 373. K.; AC
20.4	315.	C	Coolidge, 1930	AC
21.1	338.	C	Coolidge, 1930	AC
36.8	288.	N/A	Kahlbaum, 1894	Based on data from 273. to 307. K.; AC
47.7	374.	N/A	Kahlbaum, 1883	Based on data from 295. to 374. K.; AC

Enthalpy of vaporization

Δ_vapH = A exp(-αT_r) (1 − T_r)^β
Δ_vapH = Enthalpy of vaporization (at saturation pressure) (kJ/mol)
T_r = reduced temperature (T / T_c)

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Temperature (K)	298. to 374.
A (kJ/mol)	23.8
α	2.1043
β	-1.2652
T_c (K)	580.
Reference	Majer and Svoboda, 1985

Antoine Equation Parameters

log₁₀(P) = A − (B / (T + C))
P = vapor pressure (bar)
T = temperature (K)

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Temperature (K)	A	B	C	Reference	Comment
273.7 to 307.4	2.00121	515.	-139.408	Kahlbaum, 1894, 2	Coefficents calculated by NIST from author's data.

Enthalpy of sublimation

Δ_subH (kJ/mol)	Temperature (K)	Method	Reference	Comment
60.5	275.	N/A	Stephenson and Malanowski, 1987	Based on data from 268. to 281. K.; AC
62. ± 1.	213.	TE,ME	Calis-Van Ginkel, Calis, et al., 1978	Based on data from 203. to 218. K.; AC
60.1	264.	A	Stull, 1947	Based on data from 253. to 275. K.; AC
60.7	266.	N/A	Coolidge, 1930	Based on data from 265. to 268. K. See also Jones, 1960.; AC

Enthalpy of fusion

Δ_fusH (kJ/mol)	Temperature (K)	Reference	Comment
12.678	281.40	Stout and Fisher, 1941	DH

Entropy of fusion

Δ_fusS (J/mol*K)	Temperature (K)	Reference	Comment
45.05	281.40	Stout and Fisher, 1941	DH

In addition to the Thermodynamics Research Center (TRC) data available from this site, much more physical and chemical property data is available from the following TRC products:

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Notes

Guthrie, 1974
Guthrie, J.P., Hydration of carboxamides. Evaluation of the free energy change for addition of water to acetamide and formamide derivatives, J. Am. Chem. Soc., 1974, 96, 3608-3615. [all data]

Lebedeva, 1964
Lebedeva, N.D., Heats of combustion of monocarboxylic acids, Russ. J. Phys. Chem. (Engl. Transl.), 1964, 38, 1435-1437. [all data]

Konicek and Wadso, 1970
Konicek, J.; Wadso, I., Enthalpies of vaporization of organic compounds. VII. Some carboxylic acids, Acta Chem. Scand., 1970, 24, 2612-26. [all data]

Sinke, 1959
Sinke, G.C., The heat of formation of formic acid, J. Phys. Chem., 1959, 63, 2063. [all data]

Millikan R.C., 1957
Millikan R.C., Infrared spectra and vibrational assignment of monomeric formic acid, J. Chem. Phys., 1957, 27, 1305-1308. [all data]

Halford J.O., 1942
Halford J.O., Entropy of the monomeric forms of formic acid and acetic acid, J. Chem. Phys., 1942, 10, 582-584. [all data]

Waring W., 1952
Waring W., Some thermodynamic properties of formic acid, Chem. Rev., 1952, 51, 171-183. [all data]

Chao J., 1986
Chao J., Thermodynamic properties of key organic oxygen compounds in the carbon range C1 to C4. Part 2. Ideal gas properties, J. Phys. Chem. Ref. Data, 1986, 15, 1369-1436. [all data]

Fukushima K., 1971
Fukushima K., Normal coordinate treatment and thermodynamic properties of the cis-trans isomers of formic acid and its deutero-analog, J. Chem. Thermodyn., 1971, 3, 553-562. [all data]

East A.L.L., 1997
East A.L.L., Ab initio statistical thermodynamical models for the computation of third-law entropies, J. Chem. Phys., 1997, 106, 6655-6674. [all data]

Green J.H.S., 1961
Green J.H.S., Thermodynamic properties of organic oxygen compounds. Part III. Formic acid, J. Chem. Soc., 1961, 2241-2242. [all data]

Gurvich, Veyts, et al., 1989
Gurvich, L.V.; Veyts, I.V.; Alcock, C.B., Thermodynamic Properties of Individual Substances, 4th ed.; Vols. 1 and 2, Hemisphere, New York, 1989. [all data]

Chao J., 1978
Chao J., Ideal gas thermodynamic properties of methanoic and ethanoic acids, J. Phys. Chem. Ref. Data, 1978, 7, 363-377. [all data]

Stout and Fisher, 1941
Stout, J.W.; Fisher, L.H., The entropy of formic acid. The heat capacity from 15 to 300K. Heats of fusion and vaporization, J. Chem. Phys., 1941, 9, 163-168. [all data]

Parks, Kelley, et al., 1929
Parks, G.S.; Kelley, K.K.; Huffman, H.M., Thermal data on organic compounds. V. A revision of the entropies and free energies of nineteen organic compounds, J. Am. Chem. Soc., 1929, 51, 1969-1973. [all data]

Gibson, Latimer, et al., 1920
Gibson, G.E.; Latimer, W.M.; Parks, G.S., Entropy changes at low temperatures. I. Formic acid and urea. A test of the third law of thermodynamics, J. Am. Chem. Soc., 1920, 42, 1533-1542. [all data]

Glagoleva and Chervov, 1936
Glagoleva, A.A.; Chervov, S.I., Investigation of the heat capacity of formic acid and its aqueous solutions, Zhur. Obshch. Khim., 1936, 6, 685-690. [all data]

Radulescu and Jula, 1934
Radulescu, D.; Jula, O., Beiträge zur Bestimmung der Abstufung der Polarität des Aminstickstoffes in den organischen Verbindungen, Z. Phys. Chem., 1934, B26, 390-393. [all data]

von Reis, 1881
von Reis, M.A., Die specifische Wärme flüssiger organischer Verbindungen und ihre Beziehung zu deren Moleculargewicht, Ann. Physik [3], 1881, 13, 447-464. [all data]

Wilhoit, Chao, et al., 1985
Wilhoit, R.C.; Chao, J.; Hall, K.R., Thermodynamic Properties of Key Organic Compounds in the Carbon Range C1 to C4. Part 1. Properties of Condensed Phases, J. Phys. Chem. Ref. Data, 1985, 14, 1. [all data]

Stout and Fisher, 1941, 2
Stout, J.W.; Fisher, L.H., The entropy of formic acid. The heat capacity from 15 to 300 K. Heats of fusion and vaporization, J. Chem. Phys., 1941, 9, 163-8. [all data]

Taylor and Bruton, 1952
Taylor, M.D.; Bruton, J., The vapour phase dissociation of some carboxylic acids. II. Formic and propionic acids., J. Am. Chem. Soc., 1952, 74, 4151. [all data]

Anselme and Teja, 1990
Anselme, M.J.; Teja, A.S., The critical properties of rapidly reacting substances, AIChE Symp. Ser., 1990, 86, 279, 128-32. [all data]

Ambrose and Ghiassee, 1987
Ambrose, D.; Ghiassee, N.B., Vapor Pressures and Critical Temperatures and Critical Pressures of Some Alkanoic Acids: C1 to C10, J. Chem. Thermodyn., 1987, 19, 505. [all data]

Majer and Svoboda, 1985
Majer, V.; Svoboda, V., Enthalpies of Vaporization of Organic Compounds: A Critical Review and Data Compilation, Blackwell Scientific Publications, Oxford, 1985, 300. [all data]

Stephenson and Malanowski, 1987
Stephenson, Richard M.; Malanowski, Stanislaw, Handbook of the Thermodynamics of Organic Compounds, 1987, https://doi.org/10.1007/978-94-009-3173-2 . [all data]

Konicek, Wadsö, et al., 1970
Konicek, Jiri; Wadsö, Ingemar; Munch-Petersen, J.; Ohlson, Ragnar; Shimizu, Akira, Enthalpies of Vaporization of Organic Compounds. VII. Some Carboxylic Acids., Acta Chem. Scand., 1970, 24, 2612-2616, https://doi.org/10.3891/acta.chem.scand.24-2612 . [all data]

Stout and Fisher, 1941, 3
Stout, J.W.; Fisher, Leon H., The Entropy of Formic Acid. The Heat Capacity from 15 to 300°K. Heats of Fusion and Vaporization, J. Chem. Phys., 1941, 9, 2, 163, https://doi.org/10.1063/1.1750869 . [all data]

Ambrose and Ghiassee, 1987, 2
Ambrose, D.; Ghiassee, N.B., Vapour pressures and critical temperatures and critical pressures of some alkanoic acids: C1 to C10, The Journal of Chemical Thermodynamics, 1987, 19, 5, 505-519, https://doi.org/10.1016/0021-9614(87)90147-9 . [all data]

Dreisbach and Shrader, 1949
Dreisbach, R.R.; Shrader, S.A., Vapor Pressure--Temperature Data on Some Organic Compounds, Ind. Eng. Chem., 1949, 41, 12, 2879-2880, https://doi.org/10.1021/ie50480a054 . [all data]

Dreisbach and Martin, 1949
Dreisbach, R.R.; Martin, R.A., Physical Data on Some Organic Compounds, Ind. Eng. Chem., 1949, 41, 12, 2875-2878, https://doi.org/10.1021/ie50480a053 . [all data]

Campbell and Campbell, 1934
Campbell, Alan Newton; Campbell, Alexandra Jean Robson, The thermodynamics of binary liquid mixtures : formic acid and water, Trans. Faraday Soc., 1934, 30, 1109, https://doi.org/10.1039/tf9343001109 . [all data]

Coolidge, 1930
Coolidge, Albert Sprague, THE VAPOR PRESSURE AND HEATS OF FUSION AND VAPORIZATION OF FORMIC ACID, J. Am. Chem. Soc., 1930, 52, 5, 1874-1887, https://doi.org/10.1021/ja01368a018 . [all data]

Kahlbaum, 1894
Kahlbaum, G.W.A., Z. Phys. Chem., Stoechiom. Verwandtschaftsl., 1894, 13, 14. [all data]

Kahlbaum, 1883
Kahlbaum, Georg W.A., Ueber die Abhängigkeit der Siedetemperatur vom Luftdruck, Ber. Dtsch. Chem. Ges., 1883, 16, 2, 2476-2484, https://doi.org/10.1002/cber.188301602178 . [all data]

Kahlbaum, 1894, 2
Kahlbaum, G.W.A., Studien uber Dampfspannkraftsmessungen, Z. Phys. Chem. (Leipzig), 1894, 13, 14-55. [all data]

Calis-Van Ginkel, Calis, et al., 1978
Calis-Van Ginkel, C.H.D.; Calis, G.H.M.; Timmermans, C.W.M.; de Kruif, C.G.; Oonk, H.A.J., Enthalpies of sublimation and dimerization in the vapour phase of formic, acetic, propanoic, and butanoic acids, The Journal of Chemical Thermodynamics, 1978, 10, 11, 1083-1088, https://doi.org/10.1016/0021-9614(78)90082-4 . [all data]

Stull, 1947
Stull, Daniel R., Vapor Pressure of Pure Substances. Organic and Inorganic Compounds, Ind. Eng. Chem., 1947, 39, 4, 517-540, https://doi.org/10.1021/ie50448a022 . [all data]

Jones, 1960
Jones, A.H., Sublimation Pressure Data for Organic Compounds., J. Chem. Eng. Data, 1960, 5, 2, 196-200, https://doi.org/10.1021/je60006a019 . [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, References

Symbols used in this document:

C_p,gas	Constant pressure heat capacity of gas
C_p,liquid	Constant pressure heat capacity of liquid
P_triple	Triple point pressure
S°_gas	Entropy of gas at standard conditions
S°_liquid	Entropy of liquid at standard conditions
T_boil	Boiling point
T_c	Critical temperature
T_fus	Fusion (melting) point
T_triple	Triple point temperature
Δ_cH°_liquid	Enthalpy of combustion of liquid at standard conditions
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions
Δ_fH°_liquid	Enthalpy of formation of liquid at standard conditions
Δ_fusH	Enthalpy of fusion
Δ_fusS	Entropy of fusion
Δ_subH	Enthalpy of sublimation
Δ_vapH	Enthalpy of vaporization
Δ_vapH°	Enthalpy of vaporization at standard conditions

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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