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

Geometry Comparison

MgOH (magnesium hydroxide)


distance is atom 1 (O) to atom 3 (H)

Experimental bond length is 0.940  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 0.938
PM6 0.848
composite G2 0.938
G3 0.938
G3B3 0.964
G4 0.951
CBS-Q 0.932

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 0.999 0.949 0.952 0.937 0.943 0.932   0.930 0.931 0.929 0.928 0.930 0.937 0.930 0.929   0.931 0.929
ROHF   0.949 0.952   0.938 0.933 0.934 0.929                    
density functional LSDA 1.038 0.978 0.981 0.965 0.972 0.968 0.966 0.964 0.963 0.962     0.970 0.963   0.965    
SVWN   0.978     0.972   0.962                      
BLYP 1.057 0.983 0.987 0.968 0.977 0.973 0.970 0.969 0.968 0.967           0.969    
B1B95 1.032 0.967 0.971 0.954 0.958 0.955 0.953 0.950 0.950 0.950     0.956 0.948   dnf    
B3LYP 1.038 0.972 0.975 0.957 0.964 0.960 0.958 0.955   0.953 0.949 0.953 0.962   0.952   0.953 0.949
B3LYPultrafine         0.964                       0.951  
B3PW91     0.972 0.955 0.961 0.957 0.955 0.952               0.954    
mPW1PW91   0.967   0.953 0.959 0.955 0.953 0.949 0.949 0.949           0.952    
M06-2X         0.963                          
PBEPBE   0.980     0.974 0.970 0.968 0.966 0.966 0.965 0.962   0.973 0.965        
PBEPBEultrafine         0.974                          
PBE1PBE         0.960                          
HSEh1PBE         0.960                          
TPSSh         0.958   0.956             0.952        
Moller Plesset perturbation MP2   0.969 0.973 0.959 0.963 0.954 0.961 0.949 0.950 0.949   0.949 0.955       0.951  
MP2=FULL   0.969     0.962 0.951 0.954 0.948               0.956    
MP3         0.958   0.947                      
MP3=FULL         0.955   0.947                      
MP4         2.607     0.951           0.954        
B2PLYP         0.963                 0.949        
B2PLYP=FULLultrafine         0.964                          
Configuration interaction CID         0.957     0.943                    
CISD         0.958 0.946                        
Quadratic configuration interaction QCISD   0.972     0.963   0.952 0.948         0.954 0.949        
QCISD(T)         2.603     0.951                    
Coupled Cluster CCD         0.960     0.946         0.952          
CCSD         2.621     2.703                    
CCSD(T)         0.965 0.955   0.950           0.952        

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 0.944 0.941 0.939 0.937 0.939 0.940
density functional B1B95 0.962 0.959        
B3LYP 0.967 0.966 0.960 0.961 0.960 0.960
Moller Plesset perturbation MP2 0.971 0.965 0.963 0.960 0.965 0.964
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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