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

Listing of experimental data for Mg2 (Magnesium diatomic)

Other names
Magnesium; Magnesium dimer; dimagnesium;
INChI SMILES IUPAC name
InChI=1/2Mg [Mg]=[Mg] dimagnesium
State Conformation
1Σg C*V
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 287.63 0.08 kJ mol-1 JANAF Gurvich slightly different
Hfg(0K) enthalpy of formation 288.16 0.08 kJ mol-1 JANAF Gurvich slightly different
Entropy (298.15K) entropy 240.19 0.50 J K-1 mol-1 JANAF
Integrated Heat Capacity (0 to 298.15K) integrated heat capacity 9.46   kJ mol-1 JANAF Gurvich slitghtly different
Heat Capacity (298.15K) heat capacity 24.29   J K-1 mol-1 JANAF Gurvich slitghtly different
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 51 1979HUB/HER      
Detailed diatomic data
ωe ωexe ωeye Be αe ZPE reference
51.121 1.645 0.01624 0.09287 0.003776 25.25951 2007Iri:389

vibrational zero-point energy: 25.6 cm-1
Calculated vibrational frequencies for Mg2 (Magnesium diatomic).
Rotational Constants (cm-1) rotational constants
See section I.F.4 to change rotational constant units
A B C reference comment
  0.09287   1979HUB/HER

Calculated rotational constants for Mg2 (Magnesium diatomic).

Product of moments of inertia moments of inertia
181.5186amu Å2   3.014234E-38gm cm2

Geometric Data
picture of Magnesium 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
rMgMg 3.891   1 2 1979HUB/HER re

Cartesians
Atom x (Å) y (Å) z (Å)
Mg1 0.0000 0.0000 0.0000
Mg2 0.0000 0.0000 3.8905

Atom - Atom Distances bond lengths
Distances in Å
  Mg1 Mg2
Mg1   3.8905
Mg2 3.8905  

Calculated geometries for Mg2 (Magnesium diatomic).

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

Connectivity
Atom 1 Atom 2
Mg1 Mg2

Electronic energy levels (cm-1)
Energy (cm-1) Degeneracy reference description
0 1 1979HUB/HER 1Σg
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 Mg2 (Magnesium 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.  

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