Pentane

Formula: C₅H₁₂
Molecular weight: 72.1488
IUPAC Standard InChI: InChI=1S/C5H12/c1-3-5-4-2/h3-5H2,1-2H3
IUPAC Standard InChIKey: OFBQJSOFQDEBGM-UHFFFAOYSA-N
CAS Registry Number: 109-66-0
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: n-Pentane; Skellysolve A; n-C5H12; Pentan; Pentanen; Pentani; Amyl hydride; NSC 72415
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Gas phase thermochemistry data

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

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	-35.08 ± 0.14	kcal/mol	Ccb	Good, 1970	ALS
Δ_fH°_gas	-35.16 ± 0.24	kcal/mol	Cm	Pilcher and Chadwick, 1967	ALS
Δ_fH°_gas	-35.00 ± 0.16	kcal/mol	Ccb	Prosen and Rossini, 1945	ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_gas	-844.99 ± 0.23	kcal/mol	Cm	Pilcher and Chadwick, 1967	Corresponding Δ_fHº_gas = -35.16 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS
Δ_cH°_gas	-845.27 ± 0.21	kcal/mol	Ccb	Rossini, 1934	Corresponding Δ_fHº_gas = -34.88 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity	Value	Units	Method	Reference	Comment
S°_gas	83.13 ± 0.20	cal/mol*K	N/A	Messerly G.H., 1940	Scott [ Scott D.W., 1974] has calculated the value of S(298.15 K)=349.49(0.71) J/mol*K on the basis of data [ Messerly G.H., 1940].; GT

Constant pressure heat capacity of gas

C_p,gas (cal/mol*K)	Temperature (K)	Reference	Comment
28.697 ± 0.057	298.15	Kharin V.E., 1985	Experimental data [ Sage B.H., 1937] are less accurate than selected ones. Please also see Hossenlopp I.A., 1981.; GT
30.554 ± 0.062	323.15
32.481 ± 0.065	348.15
34.405 ± 0.069	373.15
36.310 ± 0.072	398.15
38.162 ± 0.076	423.15
40.002 ± 0.079	448.15
40.179	450.
41.766 ± 0.084	473.15
43.494 ± 0.086	498.15
43.592	500.
45.191 ± 0.091	523.15
46.836	550.
50.007	600.
53.043	650.
55.664	700.

Constant pressure heat capacity of gas

C_p,gas (cal/mol*K)	Temperature (K)	Reference	Comment
22.36	200.	Scott D.W., 1974, 2	Recommended values were obtained from the consistent correlation scheme for alkanes [ Scott D.W., 1974, Scott D.W., 1974, 2]. This approach gives a better agreement with experimental data than the statistical thermodynamics calculation [ Pitzer K.S., 1944, Pitzer K.S., 1946].; GT
26.900	273.15
28.69 ± 0.02	298.15
28.829	300.
36.460	400.
43.640	500.
49.900	600.
55.301	700.
59.900	800.
63.800	900.
67.299	1000.
70.201	1100.
72.801	1200.
75.000	1300.
77.000	1400.
79.001	1500.

Gas phase ion energetics data

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Data evaluated as indicated in comments:
L - Sharon G. Lias

Data compiled as indicated in comments:
LL - Sharon G. Lias and Joel F. Liebman
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

Quantity	Value	Units	Method	Reference	Comment
IE (evaluated)	10.28 ± 0.10	eV	N/A	N/A	L

Ionization energy determinations

IE (eV)	Method	Reference	Comment
10.37	PI	Traeger, Hudson, et al., 1996	T = 0K; LL
10.43	EST	Luo and Pacey, 1992	LL
10.22 ± 0.05	EI	Holmes and Lossing, 1991	LL
10.28 ± 0.10	EVAL	Lias, 1982	LBLHLM
10.18 ± 0.15	EQ	Mautner(Meot-Ner), Sieck, et al., 1981	LLK
10.93	PE	Kimura, Katsumata, et al., 1981	LLK
10.2 ± 0.1	PE	Bieri, Burger, et al., 1977	LLK
10.50	EQ	Lias, Ausloos, et al., 1976	LLK
10.36	PE	Ikuta, Yoshihara, et al., 1973	LLK
10.59 ± 0.05	EI	Flesch and Svec, 1973	LLK
10.37	PE	Dewar and Worley, 1969	RDSH
10.35	PI	Watanabe, Nakayama, et al., 1962	RDSH
10.9 ± 0.1	PE	Bieri, Burger, et al., 1977	Vertical value; LLK

Appearance energy determinations

Ion	AE (eV)	Other Products	Method	Reference	Comment
C₃H₆⁺	11.02	C₂H₆	PI	Traeger, Hudson, et al., 1996	T = 0K; LL
C₃H₆⁺	10.99 ± 0.02	C₂H₆	PI	Steiner, Giese, et al., 1961	RDSH
C₃H₇⁺	11.13	C₂H₅	PI	Traeger, Hudson, et al., 1996	T = 0K; LL
C₃H₇⁺	11.11 ± 0.05	C₂H₅	PI	Steiner, Giese, et al., 1961	RDSH
C₄H₈⁺	11.05	CH₄	PI	Traeger, Hudson, et al., 1996	T = 0K; LL
C₄H₈⁺	11.00	CH₄	EI	Wolkoff and Holmes, 1978	LLK
C₄H₈⁺	10.93 ± 0.03	CH₄	PI	Steiner, Giese, et al., 1961	RDSH
C₄H₉⁺	11.10	CH₃	PI	Traeger, Hudson, et al., 1996	T = 0K; LL
C₄H₉⁺	11.0 ± 0.1	CH₃	EI	Burgers and Holmes, 1982	LBLHLM
C₄H₉⁺	10.98 ± 0.05	CH₃	EI	Lossing and Semeluk, 1970	RDSH
C₄H₉⁺	11.06 ± 0.07	CH₃	PI	Steiner, Giese, et al., 1961	RDSH

References

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Good, 1970
Good, W.D., The enthalpies of combustion and formation of the isomeric pentanes, J. Chem. Thermodyn., 1970, 2, 237-244. [all data]

Pilcher and Chadwick, 1967
Pilcher, G.; Chadwick, J.D.M., Measurements of heats of combustion by flame calorimetry. Part 4.-n-Pentane, isopentane, neopentane, Trans. Faraday Soc., 1967, 63, 2357-2361. [all data]

Prosen and Rossini, 1945
Prosen, E.J.; Rossini, F.D., Heats of combustion and formation of the paraffin hydrocarbons at 25° C, J. Res. NBS, 1945, 263-267. [all data]

Rossini, 1934
Rossini, F.D., Calorimetric determination of the heats of combustion of ethane, propane, normal butane, and normal pentane, J. Res. NBS, 1934, 12, 735-750. [all data]

Messerly G.H., 1940
Messerly G.H., The heat capacity and entropy, heats of fusion and vaporization and the vapor pressure of n-pentane, J. Am. Chem. Soc., 1940, 62, 2988-2991. [all data]

Scott D.W., 1974
Scott D.W., Correlation of the chemical thermodynamic properties of alkane hydrocarbons, J. Chem. Phys., 1974, 60, 3144-3165. [all data]

Kharin V.E., 1985
Kharin V.E., Isobaric heat capacity of n-pentane in the vapor phase, Izv. Vyssh. Ucheb. Zaved., Neft. Gaz, 1985, 28, 63-66. [all data]

Sage B.H., 1937
Sage B.H., Phase equilibria in hydrocarbon systems. XX. Isobaric heat capacity of gaseous propane, n-butane, isobutane, and n-pentane, Ind. Eng. Chem., 1937, 29, 1309-1314. [all data]

Hossenlopp I.A., 1981
Hossenlopp I.A., Vapor heat capacities and enthalpies of vaporization of five alkane hydrocarbons, J. Chem. Thermodyn., 1981, 13, 415-421. [all data]

Scott D.W., 1974, 2
Scott D.W., Chemical Thermodynamic Properties of Hydrocarbons and Related Substances. Properties of the Alkane Hydrocarbons, C1 through C10 in the Ideal Gas State from 0 to 1500 K. U.S. Bureau of Mines, Bulletin 666, 1974. [all data]

Pitzer K.S., 1944
Pitzer K.S., Thermodynamics of gaseous paraffins. Specific heat and related properties, Ind. Eng. Chem., 1944, 36, 829-831. [all data]

Pitzer K.S., 1946
Pitzer K.S., The entropies and related properties of branched paraffin hydrocarbons, Chem. Rev., 1946, 39, 435-447. [all data]

Traeger, Hudson, et al., 1996
Traeger, J.C.; Hudson, C.E.; McAdoo, D.J., A photoionization study of the ion-neutral complexes [CH₃CH⁺CH₃CH₂CH₃] and [CH₃CH₂CH⁺CH₃CH₃] in the gas phase: Formation, H-transfer and C-C bond formation between partners, and channeling of energy into dissociation, J. Am. Soc. Mass Spectrom., 1996, 7, 73. [all data]

Luo and Pacey, 1992
Luo, Y.-R.; Pacey, P.D., Effects of alkyl substitution on ionization energies of alkanes and haloalkanes and on heats of formation of their molecular cations. Part 2. Alkanes and chloro-, bromo- and iodoalkanes, Int. J. Mass Spectrom. Ion Processes, 1992, 112, 63. [all data]

Holmes and Lossing, 1991
Holmes, J.L.; Lossing, F.P., Ionization energies of homologous organic compounds and correlation with molecular size, Org. Mass Spectrom., 1991, 26, 537. [all data]

Lias, 1982
Lias, S.G., Thermochemical information from ion-molecule rate constants, Ion Cyclotron Reson. Spectrom. 1982, 1982, 409. [all data]

Mautner(Meot-Ner), Sieck, et al., 1981
Mautner(Meot-Ner), M.; Sieck, L.W.; Ausloos, P., Ionization of normal alkanes: Enthalpy, entropy, structural, and isotope effects, J. Am. Chem. Soc., 1981, 103, 5342. [all data]

Kimura, Katsumata, et al., 1981
Kimura, K.; Katsumata, S.; Achiba, Y.; Yamazaki, T.; Iwata, S., Ionization energies, Ab initio assignments, and valence electronic structure for 200 molecules in Handbook of HeI Photoelectron Spectra of Fundamental Organic Compounds, Japan Scientific Soc. Press, Tokyo, 1981. [all data]

Bieri, Burger, et al., 1977
Bieri, G.; Burger, F.; Heilbronner, E.; Maier, J.P., Valence ionization enrgies of hydrocarbons, Helv. Chim. Acta, 1977, 60, 2213. [all data]

Lias, Ausloos, et al., 1976
Lias, S.G.; Ausloos, P.; Horvath, Z., Charge transfer reactions in alkane and cycloalkane systems. Estimated ionization potentials, Int. J. Chem. Kinet., 1976, 8, 725. [all data]

Ikuta, Yoshihara, et al., 1973
Ikuta, S.; Yoshihara, K.; Shiokawa, T.; Jinno, M.; Yokoyama, Y.; Ikeda, S., Photoelectron spectroscopy of cyclohexane, cyclopentane, and some related compounds, Chem. Lett., 1973, 1237. [all data]

Flesch and Svec, 1973
Flesch, G.D.; Svec, H.J., Fragmentation reactions in the mass spectrometer for C₂-C₅ alkanes, J. Chem. Soc. Faraday Trans. 2, 1973, 69, 1187. [all data]

Dewar and Worley, 1969
Dewar, M.J.S.; Worley, S.D., Photoelectron spectra of molecules. I. Ionization potentials of some organic molecules and their interpretation, J. Chem. Phys., 1969, 50, 654. [all data]

Watanabe, Nakayama, et al., 1962
Watanabe, K.; Nakayama, T.; Mottl, J., Ionization potentials of some molecules, J. Quant. Spectry. Radiative Transfer, 1962, 2, 369. [all data]

Steiner, Giese, et al., 1961
Steiner, B.; Giese, C.F.; Inghram, M.G., Photoionization of alkanes. Dissociation of excited molecular ions, J. Chem. Phys., 1961, 34, 189. [all data]

Wolkoff and Holmes, 1978
Wolkoff, P.; Holmes, J.L., Fragmentations of alkane molecular ions, J. Am. Chem. Soc., 1978, 100, 7346. [all data]

Burgers and Holmes, 1982
Burgers, P.C.; Holmes, J.L., Metastable ion studies. XIII. The measurement of appearance energies of metastable peaks, Org. Mass Spectrom., 1982, 17, 123. [all data]

Lossing and Semeluk, 1970
Lossing, F.P.; Semeluk, G.P., Free radicals by mass spectrometry. XLII.Ionization potentials and ionic heats of formation for C₁-C₄ alkyl radicals, Can. J. Chem., 1970, 48, 955. [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, References

Symbols used in this document:

AE	Appearance energy
C_p,gas	Constant pressure heat capacity of gas
IE (evaluated)	Recommended ionization energy
S°_gas	Entropy of gas at standard conditions
Δ_cH°_gas	Enthalpy of combustion of gas at standard conditions
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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