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

Geometry Comparison

MgH (magnesium monohydride)


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

Experimental bond length is 1.730  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical AM1 dnf
PM3 1.688
PM6 1.716
composite G2 1.749
G3 1.749
G3B3 1.755
G4 1.745
CBS-Q 1.749

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
hartree fock HF   1.759 1.752 1.760 1.749 1.744 1.744 1.744 1.739 1.736 1.734 1.741 1.741   1.734   1.736 1.734
ROHF   1.750 1.744   1.741 1.736 1.736 1.736                    
density functional LSDA 1.634 1.779 1.765 1.776 1.761 1.757 1.757 1.757 1.752 1.750     1.758 1.749   1.757    
SVWN   1.779     1.761   1.757                      
BLYP   1.782 1.770 1.782 1.768 1.763 1.763 1.766 1.761 1.757           1.765    
B1B95 1.628 1.768 1.758 1.767 1.753 1.750 1.750 1.751 1.746 1.743     1.750 1.741   1.749    
B3LYP 1.635 1.769 1.757 1.769 1.755 1.750 1.750 1.753   1.745 1.743 1.755 1.750   1.741   1.742 1.739
B3LYPultrafine         1.755                       1.744  
B3PW91   1.773 1.762 1.769 1.755 1.751 1.751 1.752   1.745           1.750    
mPW1PW91 1.647 1.771   1.768 1.753 1.749 1.749 1.749 1.745 1.742           1.748    
M06-2X         1.751                          
PBEPBE   1.787     1.770 1.765 1.766 1.767 1.762 1.758 1.757   1.766 1.758        
PBEPBEultrafine         1.770                          
PBE1PBE         1.757                          
HSEh1PBE         1.757                          
TPSSh         1.758   1.754             1.745        
Moller Plesset perturbation MP2   1.770 1.754 1.771 1.751 1.734 1.734 1.746 1.731 1.727   1.730 1.734   1.729 1.741 1.732 1.730
MP2=FULL   1.770     1.751 1.734 1.734 1.747             1.717 1.736    
MP3         1.756   1.736                      
MP3=FULL         1.755   1.736                      
MP4   1.787     1.761     1.758           1.737        
B2PLYP         1.751                 1.739        
Configuration interaction CID         1.764     1.761                    
CISD   1.799     1.771                          
Quadratic configuration interaction QCISD   1.799 1.801   1.771 1.746 1.746 1.767 1.741       1.744 1.743        
QCISD(T)         1.772 1.748 1.747 1.768                    
Coupled Cluster CCD   1.792     1.764 1.741 1.740 1.761         1.739          
CCSD         1.771 1.746 1.746 1.767                    
CCSD(T)   1.799     1.772 1.747 1.747 1.768 1.741   1.744   1.744 1.744   1.754 1.745  

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 1.784 1.756 1.758 1.752 1.739 1.754
density functional B1B95 1.787 1.764        
B3LYP 1.788 1.764 1.771 1.762 1.747 1.763
Moller Plesset perturbation MP2 1.795 1.767 1.768 1.756 1.753 1.765
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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