Neopentane
- Formula: C5H12
- Molecular weight: 72.1488
- IUPAC Standard InChIKey: CRSOQBOWXPBRES-UHFFFAOYSA-N
- CAS Registry Number: 463-82-1
- Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
The 3d structure may be viewed using Java or Javascript. - Other names: Propane, 2,2-dimethyl-; tert-Pentane; Tetramethylcarbon; Tetramethylmethane; 1,1,1-Trimethylethane; 2,2-Dimethylpropane; Neo-C5H12; UN 2044; Dimethylpropane
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Gas phase thermochemistry data
Go To: Top, Gas phase ion energetics data, Mass spectrum (electron ionization), 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
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔfH°gas | -167.9 ± 0.63 | kJ/mol | Ccb | Good, 1970 | ALS |
ΔfH°gas | -168.5 ± 1.0 | kJ/mol | Cm | Pilcher and Chadwick, 1967 | ALS |
ΔfH°gas | -166.0 ± 1.0 | kJ/mol | Ccb | Prosen and Rossini, 1945 | ALS |
Quantity | Value | Units | Method | Reference | Comment |
ΔcH°gas | -3514.1 ± 0.96 | kJ/mol | Cm | Pilcher and Chadwick, 1967 | Corresponding ΔfHºgas = -168.5 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS |
Constant pressure heat capacity of gas
Cp,gas (J/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
120.82 ± 0.25 | 298.15 | Hossenlopp I.A., 1981 | GT |
129.58 ± 0.26 | 323.15 | ||
138.41 ± 0.28 | 348.15 | ||
147.06 ± 0.29 | 373.15 | ||
155.46 ± 0.31 | 398.15 | ||
163.52 ± 0.32 | 423.15 | ||
171.46 ± 0.34 | 448.15 | ||
178.95 ± 0.36 | 473.15 | ||
186.42 ± 0.37 | 498.15 | ||
193.38 ± 0.39 | 523.15 |
Constant pressure heat capacity of gas
Cp,gas (J/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
80.54 | 200. | Scott D.W., 1974 | Recommended values were obtained from the consistent correlation scheme for alkanes [ Scott D.W., 1974, 2, Scott D.W., 1974]. This approach gives a better agreement with experimental data than the statistical thermodynamics calculation [ Pitzer K.S., 1946].; GT |
111.63 | 273.15 | ||
120.83 ± 0.25 | 298.15 | ||
121.55 | 300. | ||
155.98 | 400. | ||
186.98 | 500. | ||
214.64 | 600. | ||
238.91 | 700. | ||
261.08 | 800. | ||
280.33 | 900. | ||
297.90 | 1000. | ||
313.38 | 1100. | ||
327.19 | 1200. | ||
338.90 | 1300. | ||
351.46 | 1400. | ||
359.82 | 1500. |
Gas phase ion energetics data
Go To: Top, Gas phase thermochemistry data, Mass spectrum (electron ionization), References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data evaluated as indicated in comments:
L - Sharon G. Lias
Data compiled as indicated in comments:
B - John E. Bartmess
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) | ≤10.30 ± 0.08 | eV | N/A | N/A | L |
Ionization energy determinations
IE (eV) | Method | Reference | Comment |
---|---|---|---|
10.21 ± 0.04 | PE | Jonas, Schweitzer, et al., 1973 | LLK |
10.3 ± 0.1 | PE | Evans, Green, et al., 1972 | LLK |
10.40 | PE | Dewar and Worley, 1969 | RDSH |
10.35 | PI | Watanabe, Nakayama, et al., 1962 | RDSH |
10.90 | PE | Kimura, Katsumata, et al., 1981 | Vertical value; LLK |
10.9 ± 0.1 | PE | Bieri, Burger, et al., 1977 | Vertical value; LLK |
11.3 | PE | Schmidt and Wilkins, 1972 | Vertical value; LLK |
11.3 | PE | Murrell and Schmidt, 1972 | Vertical value; LLK |
Appearance energy determinations
Ion | AE (eV) | Other Products | Method | Reference | Comment |
---|---|---|---|---|---|
CH3+ | 29.5 ± 0.2 | ? | EI | Olmsted, Street, et al., 1964 | RDSH |
CH3+ | 13.14 | ? | EI | Lampe and Field, 1959 | RDSH |
C2H3+ | 17.95 | ? | EI | Lampe and Field, 1959 | RDSH |
C2H5+ | 13.81 | ? | EI | Lampe and Field, 1959 | RDSH |
C3H3+ | 17.08 | ? | EI | Lampe and Field, 1959 | RDSH |
C3H5+ | 13.13 | ? | EI | Lampe and Field, 1959 | RDSH |
C4H8+ | 10.39 ± 0.02 | CH4 | PI | Steiner, Giese, et al., 1961 | RDSH |
C4H9+ | 10.35 | CH3 | PI | Chesnavich, Su, et al., 1978 | LLK |
C4H9+ | 10.56 | CH3 | EI | Lossing and Semeluk, 1970 | RDSH |
C4H9+ | 10.57 ± 0.02 | CH3 | PI | Steiner, Giese, et al., 1961 | RDSH |
De-protonation reactions
C5H11- + =
By formula: C5H11- + H+ = C5H12
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 1711. ± 8.4 | kJ/mol | Bran | DePuy, Gronert, et al., 1989 | gas phase; B |
ΔrH° | 1720. ± 42. | kJ/mol | CIDT | Graul and Squires, 1990 | gas phase; B |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 1674. ± 8.8 | kJ/mol | H-TS | DePuy, Gronert, et al., 1989 | gas phase; B |
Mass spectrum (electron ionization)
Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics 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: NIST Mass Spectrometry Data Center, William E. Wallace, director
Spectrum
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Additional Data
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Due to licensing restrictions, this spectrum cannot be downloaded.
Owner | NIST Mass Spectrometry Data Center Collection (C) 2014 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved. |
---|---|
NIST MS number | 280 |
References
Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Mass spectrum (electron ionization), Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
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]
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
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]
Scott D.W., 1974, 2
Scott D.W.,
Correlation of the chemical thermodynamic properties of alkane hydrocarbons,
J. Chem. Phys., 1974, 60, 3144-3165. [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]
Jonas, Schweitzer, et al., 1973
Jonas, A.E.; Schweitzer, G.K.; Grimm, F.A.; Carlson, T.A.,
The photoelectron spectra of the tetrafluoro and tetramethyl compounds of the group IV elements,
J. Electron Spectrosc. Relat. Phenom., 1973, 1, 29. [all data]
Evans, Green, et al., 1972
Evans, S.; Green, J.C.; Joachim, P.J.; Orchard, A.F.; Turner, D.W.; Maier, J.P.,
Electronic structures of the Group IVB tetramethyls by helium-(I) photoelectron spectroscopy,
J. Chem. Soc. Faraday Trans. 2, 1972, 68, 905. [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]
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]
Schmidt and Wilkins, 1972
Schmidt, W.; Wilkins, B.T.,
Das "Equivalent Orbital" (EO)-verfahren zur interpretation von photoelektronen(PE)-spektren: Neopentan,
Angew. Chem., 1972, 84, 168. [all data]
Murrell and Schmidt, 1972
Murrell, J.N.; Schmidt, W.,
Photoelectron spectroscopic correlation of the molecular orbitals of methane, ethane, propane, isobutane and neopentane,
J. Chem. Soc. Faraday Trans. 2, 1972, 68, 1709. [all data]
Olmsted, Street, et al., 1964
Olmsted, J., III; Street, K., Jr.; Newton, A.S.,
Excess-kinetic-energy ions in organic mass spectra,
J. Chem. Phys., 1964, 40, 2114. [all data]
Lampe and Field, 1959
Lampe, F.W.; Field, F.H.,
The decomposition of neopentane under electron impact,
J. Am. Chem. Soc., 1959, 81, 3238. [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]
Chesnavich, Su, et al., 1978
Chesnavich, W.J.; Su, T.; Bowers, M.T.,
Reactions of vibrationally excited ions. A theoretical and experimental analysis of the reaction (C4H9+) + NH3 Ü NH4+ + C4H8,
J. Am. Chem. Soc., 1978, 100, 4362. [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]
DePuy, Gronert, et al., 1989
DePuy, C.H.; Gronert, S.; Barlow, S.E.; Bierbaum, V.M.; Damrauer, R.,
The Gas Phase Acidities of the Alkanes,
J. Am. Chem. Soc., 1989, 111, 6, 1968, https://doi.org/10.1021/ja00188a003
. [all data]
Graul and Squires, 1990
Graul, S.T.; Squires, R.R.,
Gas-Phase Acidities Derived from Threshold Energies for Activated Reactions,
J. Am. Chem. Soc., 1990, 112, 7, 2517, https://doi.org/10.1021/ja00163a007
. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Mass spectrum (electron ionization), References
- Symbols used in this document:
AE Appearance energy Cp,gas Constant pressure heat capacity of gas IE (evaluated) Recommended ionization energy ΔcH°gas Enthalpy of combustion of gas at standard conditions ΔfH°gas Enthalpy of formation of gas at standard conditions ΔrG° Free energy of reaction at standard conditions ΔrH° Enthalpy of reaction at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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