CCCBDB listing of experimental data page 2

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Property	Value	Uncertainty	units	Reference
Hfg(298.15K)	971.00	33.00	kJ mol^-1	JANAF
Hfg(0K)	964.00	33.00	kJ mol^-1	JANAF
Entropy (298.15K)	228.30	16.70	J K^-1 mol^-1	JANAF
Integrated Heat Capacity (0 to 298.15K)	10.79		kJ mol^-1	JANAF
Heat Capacity (298.15K)	50.18		J K^-1 mol^-1	JANAF

Mode Number	Symmetry	Frequency			Intensity			Comment	Description
Mode Number	Symmetry	Fundamental(cm^-1)	Harmonic(cm^-1)	Reference	(km mol^-1)	unc.	Reference	Comment	Description
1	Σ_g⁺	2057		webbook
3	Σ_u	1549		webbook
4	Π_g	323		webbook
5	Π_u	160		webbook

Description	Value	unc.	Connectivity				Reference	Comment
Description	Value	unc.	Atom 1	Atom 2	Atom 3	Atom 4	Reference	Comment
rCC	1.304	0.001	1	3			1995Kuchitsu(II/23)	assumed all CC bonds equal

Atom 1	Atom 2
C1	C2
C1	C3
C2	C4

State	Config	State description	Conf description	Exp. min.	Dipole (Debye)				Reference	comment	Point Group	Components
State	Config	State description	Conf description	Exp. min.	x	y	z	total	Reference	comment	Point Group	dipole	quadrupole
1	1	³Σ_g	D_∞h	True							D_∞h	0	1
2	1	¹Σ	D_∞h								D_∞h	0	1

	Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
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squib	reference	DOI
1995Kuchitsu(II/23)	Kuchitsu (ed.), Landolt-Bornstein: Group II: Molecules and Radicals Volume 23: Structure Data for Free Polyatomic Molecules. Springer. Berlin. 1995
JANAF	Chase, M.W., Jr.; Davies, C.A.; Downey, J.R., Jr.; Frurip, D.J.; McDonald, R.A.; Syverud, A.N., JANAF Thermochemical Tables (Third Edition), J. Phys. Chem. Ref. Data,Suppl. 1, 1985, 14, 1.
webbook	NIST Chemistry Webbook (http://webbook.nist.gov/chemistry)	10.18434/T4D303

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Experimental data for C4 (Carbon tetramer)

Experimental data for C₄ (Carbon tetramer)