Enthalpy of formation (Hfg), Entropy, Integrated heat capacity (0 K to 298.15 K) (HH), Heat Capacity (Cp)

Property	Value	Uncertainty	units	Reference	Comment
Hfg(298.15K)	0.00	0.00	kJ mol-1	CODATA
Hfg(0K)	0.00	0.00	kJ mol-1	CODATA
Entropy (298.15K)	223.08		J K-1 mol-1	CODATA
Integrated Heat Capacity (0 to 298.15K)	9.18	0.00	kJ mol-1	CODATA
Heat Capacity (298.15K)	33.95		J K-1 mol-1	Gurvich

Information can also be found for this species in the NIST Chemistry Webbook

Vibrational levels (cm^-1)

Mode Number	Symmetry	Frequency (cm-1)	Frequency Reference	Intensity (km mol-1)	Int. unc.	Intensity Reference	Comment
1	Σg	560	VEEL5

Detailed diatomic data

ωe	ωexe	ωeye	Be	αe	ZPE	reference
559.751	2.69427	-0.0033253	0.24415	0.001516	279.2222	2007Iri:389

vibrational zero-point energy: 279.9 cm^-1
Calculated vibrational frequencies for Cl₂^- (chlorine diatomic anion).

Rotational Constants (cm^-1)
See section I.F.4 to change rotational constant units

A	B	C	reference	comment
	0.24399		1979HUB/HER

Calculated rotational constants for Cl₂^- (chlorine diatomic anion).

Product of moments of inertia
69.09148	amu Å2		1.147309E-38	gm cm2

Geometric Data

Point Group D_∞h

Internal coordinates
distances (r) in Å, angles (a) in degrees, dihedrals (d) in degrees

Description	Value	unc.	Connectivity				Reference	Comment
			Atom 1	Atom 2	Atom 3	Atom 4
rClCl	1.988		1	2			1979HUB/HER

Cartesians

Atom	x (Å)	y (Å)	z (Å)
Cl1	0.0000	0.0000	0.0000
Cl2	0.0000	0.0000	1.9879

Atom - Atom Distances
Distances in Å

	Cl1	Cl2
Cl1		1.9879
Cl2	1.9879

Calculated geometries for Cl₂^- (chlorine diatomic anion).

Bond descriptions
Examples: C-C single bond, C=C, double bond, C#C triple bond, C:C aromatic bond

Bond Type	Count
Cl-Cl	1

Connectivity

Atom 1	Atom 2
Cl1	Cl2

Electronic energy levels (cm^-1)

Energy (cm-1)	Degeneracy	reference	description
0	1	1979HUB/HER	1Σg

Ionization Energies (eV)

Ionization Energy	I.E. unc.	vertical I.E.	v.I.E. unc.	Electron Affinity	E.A. unc.	reference
11.481	0.003	11.490		2.500	0.200	webbook

Dipole, Quadrupole and Polarizability
Electric dipole moment
For a molecule with D_∞h symmetry there is no dipole.
Electric quadrupole moment

Quadrupole (D Å)			Reference	comment
xx	yy	zz
-1.509	-1.509	3.019	1998Gra/Imr:49	10.07+-0.16 E-40 Cm^2

Calculated electric quadrupole moments for Cl₂^- (chlorine diatomic anion).

References
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squib	reference	DOI
1979HUB/HER	Huber, K.P.; Herzberg, G., Molecular Spectra and Molecular Structure. IV. Constants of Diatomic Molecules,, Van Nostrand Reinhold Co., 1979
1998Gra/Imr:49	C Graham, DA Imrie, RE Raab "Measurement of the electric quadrupole moments of CO2, CO, N2, Cl2 and BF3" Mol. Phys. 93(1), 1998, 49-56	10.1080/002689798169429
2007Iri:389	KK Irikura "Experimental Vibrational Zero-Point Energies: Diatomic Molecules" J. Phys. Chem. Ref. Data 36(2), 389, 2007	10.1063/1.2436891
CODATA	Cox, J.D.; Wagman, D.D.; Medvedev, V.A.CODATA Key Values for Thermodynamics. Hemisphere, New York, 1989
Gurvich	Gurvich, L.V.; Veyts, I. V.; Alcock, C. B., Thermodynamic Properties of Individual Substances, Fouth Edition, Hemisphere Pub. Co., New York, 1989	10.1351/pac198961061027
VEEL5	M.E. Jacox, Vibrational and Electronic Energy Levels of Polyatomic Transient Molecules, J. Phys. Chem.Ref. Data, Monograph 3 (1994) (updated data in NIST Chemistry Webbook - http://webbook.nist.gov/chemistry/
webbook	NIST Chemistry Webbook (http://webbook.nist.gov/chemistry)

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