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IV.D.1. (XII.C.1.)

Geometry Comparison

MgO (magnesium oxide)


distance is atom 1 (Mg) to atom 2 (O)

Experimental bond length is 1.749  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.692
PM6 1.632
composite G2 1.738
G3 1.738
G3B3 1.744
G4 1.736
CBS-Q 1.751

Calculated bond length in Å
Methods with standard basis sets
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pCVDZ cc-pCVTZ
hartree fock HF 1.706 1.776 1.728 1.807 1.738 1.738 1.750 1.751 1.751 1.722 1.718 1.780 1.748   1.721   1.727 1.721 1.743 1.716
density functional LSDA 1.645 1.741 1.721 1.761 1.730 1.730 1.746 1.742 1.742 1.722     1.737 1.728   1.738        
SVWN   1.741     1.730   1.746                          
BLYP 1.670 1.767 1.745 1.789 1.759 1.759 1.778 1.772 1.772 1.751           1.769        
B1B95 1.656 1.746 1.728 1.771 1.740 1.742 1.757 1.752 1.752 1.733     1.746 1.736   1.748     1.744 1.731
B3LYP 1.663 1.750 1.730 1.774 1.744 1.744 1.762 1.756   1.736 1.738 1.765 1.749   1.739   1.744 1.740 1.747 1.735
B3LYPultrafine         1.744                       1.743      
B3PW91   1.750 1.731 1.773 1.742 1.742 1.758 1.754   1.734           1.750        
mPW1PW91   1.747   1.770 1.739 1.739 1.755 1.750 1.750 1.730           1.747        
M06-2X         1.734                              
PBEPBE   1.765     1.756 1.756 1.773 1.768 1.768 1.747 1.750   1.762 1.754            
PBEPBEultrafine         1.756                              
PBE1PBE         1.739                              
HSEh1PBE         1.740                              
TPSSh         1.745   1.757             1.743            
Moller Plesset perturbation MP2   1.690 1.718 1.727 1.734 1.734 1.759 1.740 1.740 1.740   1.741 1.734 1.737 1.740 1.757 1.746 1.743 1.735 1.737
MP2=FULL   1.691     1.733 1.733 1.758 1.740         1.734 1.736 1.736 1.753 1.737   1.734 1.735
MP3         1.811   1.791                          
MP3=FULL         1.790   1.791                          
MP4         1.703     1.709           1.713            
B2PLYP         1.749                 1.746            
Configuration interaction CID         1.765     1.772                        
CISD         1.770                              
Quadratic configuration interaction QCISD   1.891     1.801   1.808 1.806 1.806       1.809 1.778            
QCISD(T)         1.786     1.795                        
Coupled Cluster CCD         1.780     1.789         1.786 1.770         1.785 1.764
CCSD         1.795     1.802                        
CCSD(T)   1.775     1.770 1.770 1.791 1.776 1.775   1.760     1.760     1.766   1.772 1.753
CCSD(T)=FULL         1.768               1.775 1.754         1.769 1.743

Calculated bond length in Å
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 1.841 1.761 1.812 1.743 1.776 1.813
density functional B1B95 1.795 1.755        
B3LYP 1.803 1.763 1.785 1.753 1.759 1.780
Moller Plesset perturbation MP2 1.756 1.745 1.737 1.738 1.730 1.740
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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