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

Geometry Comparison

C3H4N2 (1H-Imidazole)


distance is atom 5 (C) to atom 6 (H)

Experimental bond length is 1.078  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.088
PM6 1.020
composite G3 1.070
G3B3 1.082
G4 1.080
CBS-Q 1.073

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 aug-cc-pVDZ aug-cc-pVTZ
hartree fock HF 1.079 1.062 1.062 1.064 1.070 1.070 1.070 1.070 1.070 1.070 1.068 1.050 1.077 1.068 1.075 1.068
density functional LSDA 1.096 1.086 1.086 1.087 1.091 1.091 1.091 1.090 1.089 1.089     1.098 1.087 1.095  
BLYP 1.103 1.083 1.083 1.084 1.089 1.088 1.087 1.087 1.085 1.086     1.095 1.083 1.092  
B1B95 1.093 1.074 1.074 1.075 1.080 1.080 1.079 1.079 1.078 1.078     1.086 1.075 1.083  
B3LYP 1.095 1.075 1.075 1.077 1.082 1.081   1.080   1.079 1.077 1.048 1.088 1.077    
B3LYPultrafine         1.082   1.081             1.077   1.077
B3PW91   1.076 1.076 1.077 1.082 1.081 1.081 1.081   1.080     1.088 1.078 1.086  
mPW1PW91   1.074   1.075 1.080 1.080 1.080 1.079 1.078 1.079     1.087   1.084  
M06-2X         1.049                      
PBEPBE   1.084     1.090 1.089 1.089 1.088 1.087 1.088 1.086   1.096 1.086    
PBEPBEultrafine         1.090                      
PBE1PBE         1.082                      
TPSSh         1.082   1.081             1.078    
Moller Plesset perturbation MP2   1.077 1.077 1.081 1.082 1.077 1.077 1.081 1.080 1.078   1.047 1.090      
MP2=FULL         1.081 1.076 1.076 1.081                
MP3         1.081   1.075                  
MP3=FULL         1.081   1.074                  
B2PLYP                           1.075    
B2PLYP=FULLultrafine         1.080                      
Configuration interaction CID         1.075                      
CISD         1.075                      
Quadratic configuration interaction QCISD   1.080     1.083       1.081              
Coupled Cluster CCD         1.083                      

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 1.070 1.076 1.067 1.072 1.064 1.064
density functional B1B95 1.085 1.089        
B3LYP 1.085 1.090 1.080 1.084 1.079 1.079
Moller Plesset perturbation MP2 1.092 1.091 1.085 1.083 1.085 1.084
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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