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II.A.1. (XV.A.)

Listing of experimental data for Na2 (Sodium diatomic)

Other names
Sodium; Sodium dimer; disodium;
INChI SMILES IUPAC name
InChI=1/2Na [Na][Na] disodium
State Conformation
1Σg D*H
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) enthalpy of formation 142.07 1.20 kJ mol-1 JANAF
Hfg(0K) enthalpy of formation 144.59 1.20 kJ mol-1 JANAF
Entropy (298.15K) entropy 230.24 0.03 J K-1 mol-1 JANAF
Integrated Heat Capacity (0 to 298.15K) integrated heat capacity 10.40   kJ mol-1 JANAF
Heat Capacity (298.15K) heat capacity 37.59   J K-1 mol-1 webbook
Information can also be found for this species in the NIST Chemistry Webbook
Vibrational levels (cm-1) vibrations
Mode Number Symmetry Frequency (cm-1) Frequency Reference Intensity (km mol-1) Int. unc. Intensity Reference Comment
1 Σg 159 1979HUB/HER      
Detailed diatomic data
ωe ωexe ωeye Be αe ZPE reference
159.0855 0.7086557 -4.632416E-03 0.1547354 8.63753E-04 79.33591 2007Iri:389

vibrational zero-point energy: 79.6 cm-1
Calculated vibrational frequencies for Na2 (Sodium diatomic).
Rotational Constants (cm-1) rotational constants
See section I.F.4 to change rotational constant units
A B C reference comment
  0.15471   1979HUB/HER

Calculated rotational constants for Na2 (Sodium diatomic).

Product of moments of inertia moments of inertia
108.9649amu Å2   1.809433E-38gm cm2

Geometric Data
picture of Sodium diatomic

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
rNaNa 3.079   1 2 1979HUB/HER re

Cartesians
Atom x (Å) y (Å) z (Å)
Na1 0.0000 0.0000 0.0000
Na2 0.0000 0.0000 3.0789

Atom - Atom Distances bond lengths
Distances in Å
  Na1 Na2
Na1   3.0789
Na2 3.0789  

Calculated geometries for Na2 (Sodium diatomic).

Bond descriptions
Examples: C-C single bond, C=C, double bond, C#C triple bond, C:C aromatic bond
Bond Type Count
Na-Na 1

Connectivity
Atom 1 Atom 2
Na1 Na2

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. reference
4.892 0.003     webbook

Electron Affinity (eV)
Electron Affinity unc. reference
0.430 0.015 webbook

Dipole, Quadrupole and Polarizability
Electric dipole moment dipole
For a molecule with D∞h symmetry there is no dipole.
Electric quadrupole moment quadrupole
Calculated electric quadrupole moments for Na2 (Sodium diatomic).

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  
2007Iri:389 KK Irikura "Experimental Vibrational Zero-Point Energies: Diatomic Molecules" J. Phys. Chem. Ref. Data 36(2), 389, 2007 10.1063/1.2436891
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)  

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