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

Geometry Comparison

C3H4N2 (1H-Imidazole)


distance is atom 7 (H) to atom 8 (C)

Experimental bond length is 1.079  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.092
PM6 1.020
composite G3 1.071
G3B3 1.082
G4 1.081
CBS-Q 1.074

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 1.083 1.063 1.063 1.064 1.071 1.071 1.071 1.071 1.071 1.071 1.070 1.048 1.078 1.070 1.076 1.069
density functional LSDA 1.098 1.086 1.086 1.086 1.092 1.091 1.091 1.090 1.089 1.089     1.098 1.088 1.095  
BLYP 1.105 1.083 1.083 1.084 1.089 1.088 1.087 1.087 1.085 1.086     1.095 1.083 1.091  
B1B95 1.095 1.075 1.075 1.075 1.080 1.080 1.080 1.079 1.078 1.079     1.086 1.076 1.083  
B3LYP 1.097 1.076 1.076 1.077 1.082 1.081   1.080   1.080 1.077 1.046 1.088 1.077    
B3LYPultrafine         1.082   1.081             1.079   1.078
B3PW91   1.076 1.076 1.077 1.082 1.082 1.081 1.081   1.081     1.088 1.079 1.085  
mPW1PW91   1.075   1.075 1.081 1.080 1.080 1.080 1.079 1.079     1.087   1.084  
M06-2X         1.047                      
PBEPBE   1.085     1.090 1.089 1.089 1.088 1.087 1.088 1.086   1.096 1.086    
PBEPBEultrafine         1.092                      
PBE1PBE         1.082                      
TPSSh         1.083   1.082             1.080    
Moller Plesset perturbation MP2   1.077 1.077 1.081 1.082 1.077 1.079 1.081 1.081 1.078   1.046 1.090      
MP2=FULL         1.081 1.076 1.076 1.081                
MP3         1.081   1.077                  
MP3=FULL         1.083   1.076                  
B2PLYP                           1.076    
B2PLYP=FULLultrafine         1.082                      
Configuration interaction CID         1.076                      
CISD         1.076                      
Quadratic configuration interaction QCISD   1.081     1.084       1.082              
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 1.071 1.078 1.068 1.074 1.064 1.064
density functional B1B95 1.086 1.091        
B3LYP 1.086 1.091 1.080 1.085 1.079 1.079
Moller Plesset perturbation MP2 1.092 1.091 1.085 1.083 1.084 1.084
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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