Cubane

Formula: C₈H₈
Molecular weight: 104.1491
IUPAC Standard InChI: InChI=1S/C8H8/c1-2-5-3(1)7-4(1)6(2)8(5)7/h1-8H
IUPAC Standard InChIKey: TXWRERCHRDBNLG-UHFFFAOYSA-N
CAS Registry Number: 277-10-1
Chemical structure:
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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

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas			Ccb	Kybett, Carroll, et al., 1966	uncertain value: 622.2 ± 4.2 kJ/mol; ALS
Δ_fH°_gas	597.1 ± 5.0	kJ/mol	Ccb	Kybett, Carroll, et al., 1966, 2	Value recomputed with updated enthalpy of sublimation from Bashir-Hashemi, Chickos, et al., 2004. The value used in the original paper is now deemed unreliable.

Condensed phase thermochemistry data

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Data compiled by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_solid	542. ± 3.	kJ/mol	Ccb	Kybett, Carroll, et al., 1966
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_solid	-4833.27	kJ/mol	Ccb	Kybett, Carroll, et al., 1966	Corresponding Δ_fHº_solid = 541.87 kJ/mol (simple calculation by NIST; no Washburn corrections)

Phase change data

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Data compiled as indicated in comments:
AC - William E. Acree, Jr., James S. Chickos
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
CAL - James S. Chickos, William E. Acree, Jr., Joel F. Liebman, Students of Chem 202 (Introduction to the Literature of Chemistry), University of Missouri -- St. Louis
DH - Eugene S. Domalski and Elizabeth D. Hearing

Quantity	Value	Units	Method	Reference	Comment
Δ_vapH°	44.6 ± 0.8	kJ/mol	CGC	Bashir-Hashemi, Chickos, et al., 2004	AC
Quantity	Value	Units	Method	Reference	Comment
Δ_subH°	55.2 ± 2.0	kJ/mol	AC+CGC	Bashir-Hashemi, Chickos, et al., 2004	AC
Δ_subH°			ME	Kybett, Carroll, et al., 1966, 2	uncertain value: 80.3 ± 1.6 kJ/mol; in Ref. Diky, Frenkel, et al., 2003 the authors state that the value of 80.3 kJ/mole from Kybett, Carroll, et al., 1966, 2 pertains to the average temperature and not to 298 K. The authors give a value of 79.1±1.7 for the 298 K value; AC

Enthalpy of sublimation

Δ_subH (kJ/mol)	Temperature (K)	Method	Reference	Comment
80. ± 2.	239.	V	Kybett, Carroll, et al., 1966	ALS

Enthalpy of fusion

Δ_fusH (kJ/mol)	Temperature (K)	Method	Reference	Comment
8.7	404.9	AC	White, Wasylishen, et al., 1992	AC

Entropy of fusion

Δ_fusS (J/mol*K)	Temperature (K)	Reference	Comment
15.08	394.	White, Wasylishen, et al., 1992, 2	CAL
21.49	404.9	White, Wasylishen, et al., 1992, 2	CAL

Enthalpy of phase transition

ΔH_trs (kJ/mol)	Temperature (K)	Initial Phase	Final Phase	Reference	Comment
5.940	395.04	crystaline, II	crystaline, I	White, Wasylishen, et al., 1992	DH
8.700	404.9	crystaline, I	liquid	White, Wasylishen, et al., 1992	DH

Entropy of phase transition

ΔS_trs (J/mol*K)	Temperature (K)	Initial Phase	Final Phase	Reference	Comment
15.37	395.04	crystaline, II	crystaline, I	White, Wasylishen, et al., 1992	DH
22.7	404.9	crystaline, I	liquid	White, Wasylishen, et al., 1992	DH

Reaction thermochemistry data

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Data compiled by: John E. Bartmess

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.

Individual Reactions

C₈H₇^- + = Cubane

By formula: C₈H₇^- + H⁺ = C₈H₈

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1688. ± 13.	kJ/mol	G+TS	Hare, Emrick, et al., 1997	gas phase; Comparable to ammonia; D exchange with ND3
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1659. ± 13.	kJ/mol	IMRB	Hare, Emrick, et al., 1997	gas phase; Comparable to ammonia; D exchange with ND3

Gas phase ion energetics data

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Data evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
L - Sharon G. Lias

Data compiled as indicated in comments:
B - John E. Bartmess
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

View reactions leading to C₈H₈⁺ (ion structure unspecified)

Quantity	Value	Units	Method	Reference	Comment
IE (evaluated)	8.6 ± 0.1	eV	N/A	N/A	L
Quantity	Value	Units	Method	Reference	Comment
Proton affinity (review)	859.9	kJ/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Gas basicity	833.6	kJ/mol	N/A	Hunter and Lias, 1998	HL

Ionization energy determinations

IE (eV)	Method	Reference	Comment
8.6 ± 0.1	TRPI	Lifshitz and Eaton, 1983	LBLHLM
8.46	PE	Gassman and Yamaguchi, 1979	LLK
8.6	PE	Bischof, Eaton, et al., 1978	LLK
8.4 ± 0.1	EI	Gross, 1972	LLK
8.64 ± 0.10	EI	Franklin and Carroll, 1969	RDSH
8.74	PE	Dewar and Worley, 1969	RDSH
8.74 ± 0.15	EI	Kybett, Carroll, et al., 1966	RDSH
9.00	PE	Bischof, Eaton, et al., 1978	Vertical value; LLK

Appearance energy determinations

Ion	AE (eV)	Other Products	Method	Reference	Comment
C₃H₃⁺	10.01 ± 0.10	?	EI	Franklin and Carroll, 1969	RDSH
C₄H₂⁺	14.33 ± 0.20	2C₂H₂+H₂	EI	Franklin and Carroll, 1969	RDSH
C₄H₃⁺	14.96 ± 0.10	2C₂H₂+H	EI	Franklin and Carroll, 1969	RDSH
C₄H₄⁺	12.88 ± 0.15	2C₂H₂	EI	Franklin and Carroll, 1969	RDSH
C₅H₃⁺	13.60 ± 0.10	?	EI	Franklin and Carroll, 1969	RDSH
C₆H₅⁺	10.93 ± 0.10	C₂H₂+H	EI	Franklin and Carroll, 1969	RDSH
C₆H₆⁺	8.8 ± 0.1	C₂H₂	TRPI	Lifshitz and Eaton, 1983	LBLHLM
C₆H₆⁺	9.2 ± 0.1	?	EI	Gross, 1972	LLK
C₆H₆⁺	9.00 ± 0.10	C₂H₂	EI	Franklin and Carroll, 1969	RDSH
C₈H₆⁺	8.92 ± 0.10	H₂	EI	Franklin and Carroll, 1969	RDSH
C₈H₇⁺	9.3 ± 0.2	H	TRPI	Lifshitz and Eaton, 1983	LBLHLM
C₈H₇⁺	8.96 ± 0.10	H	EI	Franklin and Carroll, 1969	RDSH

De-protonation reactions

C₈H₇^- + = Cubane

By formula: C₈H₇^- + H⁺ = C₈H₈

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1688. ± 13.	kJ/mol	G+TS	Hare, Emrick, et al., 1997	gas phase; Comparable to ammonia; D exchange with ND3; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1659. ± 13.	kJ/mol	IMRB	Hare, Emrick, et al., 1997	gas phase; Comparable to ammonia; D exchange with ND3; B

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, NIST Free Links, Notes

Kybett, Carroll, et al., 1966
Kybett, B.D.; Carroll, S.; Natalis, P.; Bonnell, D.W.; Margrave, J.L.; Franklin, J.L., Thermodynamic properties of cubane, J. Am. Chem. Soc., 1966, 88, 626. [all data]

Kybett, Carroll, et al., 1966, 2
Kybett, B.D.; Carroll, S.; Natalis, P.; Bonnell, D.W.; Margrave, J.L.; Franklin, J.L., Thermodynamic Properties of Cubane, J. Am. Chem. Soc., 1966, 88, 3, 626-626, https://doi.org/10.1021/ja00955a056 . [all data]

Bashir-Hashemi, Chickos, et al., 2004
Bashir-Hashemi, A.; Chickos, James S.; Hanshaw, William; Zhao, Hui; Farivar, Behzad S.; Liebman, Joel F., The enthalpy of sublimation of cubane, Thermochimica Acta, 2004, 424, 1-2, 91-97, https://doi.org/10.1016/j.tca.2004.05.022 . [all data]

Diky, Frenkel, et al., 2003
Diky, Vladimir V.; Frenkel, Michael; Karpushenkava, Larisa S., Thermodynamics of sublimation of cubane: natural anomaly or experimental error?, Thermochimica Acta, 2003, 408, 1-2, 115-121, https://doi.org/10.1016/S0040-6031(03)00318-6 . [all data]

White, Wasylishen, et al., 1992
White, M.A.; Wasylishen, R.E.; Eaton, P.E.; Xiong, Y.; Pramod, K.; Nodari, N., Orientational disorder in solid cubane: a thermodynamic and 13C NMR study, J. Phys. Chem., 1992, 96(1), 421-425. [all data]

White, Wasylishen, et al., 1992, 2
White, M.A.; Wasylishen, R.E.; Eaton, P.E.; Xiong, Y.; Pramod, K.; Nodari, N., Orientational disorder in solid cubane: a thermodynamic and carbon-13 NMR study, J. Phys. Chem., 1992, 96, 1, 421, https://doi.org/10.1021/j100180a078 . [all data]

Hare, Emrick, et al., 1997
Hare, M.; Emrick, T.; Eaton, P.E.; Kass, S.R., Cubyl Anion Formation and an Experimental Determination of the Acidity and C-H Bond Dissociation Energy of Cubane, J. Am. Chem. Soc., 1997, 119, 1, 237, https://doi.org/10.1021/ja9627858 . [all data]

Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G., Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update, J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, https://doi.org/10.1063/1.556018 . [all data]

Lifshitz and Eaton, 1983
Lifshitz, C.; Eaton, P.E., Time-dependent mass spectra and breakdown graphs. III. The cubane cation complete or partial instability, Int. J. Mass Spectrom. Ion Phys., 1983, 49, 337. [all data]

Gassman and Yamaguchi, 1979
Gassman, P.G.; Yamaguchi, R., Electrochemical oxidation of strained hydrocarbons, J. Am. Chem. Soc., 1979, 101, 1308. [all data]

Bischof, Eaton, et al., 1978
Bischof, P.; Eaton, P.E.; Gleiter, R.; Heilbronner, E.; Jones, T.B.; Musso, H.; Schmelzer, A.; Stober, R., 44. The electronic structure of cubane (C₈H₈) as revealed by photoelectron spectroscopy, Helv. Chim. Acta, 1978, 61, 547. [all data]

Gross, 1972
Gross, M.L., Ion cyclotron resonance spectrometry. A means of evaluating 'kinetic shifts', Org. Mass Spectrom., 1972, 6, 827. [all data]

Franklin and Carroll, 1969
Franklin, J.L.; Carroll, S.R., The effect of molecular structure on ionic decomposition. I. An electron impact study of seven C₈H₈ isomers, J. Am. Chem. Soc., 1969, 91, 5940. [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]

Notes

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Symbols used in this document:

AE	Appearance energy
IE (evaluated)	Recommended ionization energy
ΔH_trs	Enthalpy of phase transition
ΔS_trs	Entropy of phase transition
Δ_cH°_solid	Enthalpy of combustion of solid at standard conditions
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions
Δ_fH°_solid	Enthalpy of formation of solid at standard conditions
Δ_fusH	Enthalpy of fusion
Δ_fusS	Entropy of fusion
Δ_rG°	Free energy of reaction at standard conditions
Δ_rH°	Enthalpy of reaction at standard conditions
Δ_subH	Enthalpy of sublimation
Δ_subH°	Enthalpy of sublimation at standard conditions
Δ_vapH°	Enthalpy of vaporization at standard conditions

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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