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

Geometry Comparison

C3H4N2 (1H-Imidazole)


distance is atom 3 (C) to atom 4 (H)

Experimental bond length is 1.079  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.089
PM6 1.019
composite G3 1.068
G3B3 1.079
G4 1.077
CBS-Q 1.071

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 1.063 1.063 1.064 1.068 1.069 1.069 1.068 1.068 1.068 1.067 1.048 1.076 1.066 1.074 1.066
density functional LSDA 1.095 1.085 1.085 1.086 1.089 1.088 1.089 1.088 1.086 1.087     1.095 1.085 1.093  
BLYP 1.102 1.082 1.082 1.084 1.087 1.086 1.086 1.085 1.083 1.084     1.093 1.081 1.090  
B1B95 1.092 1.074 1.074 1.075 1.077 1.077 1.078 1.077 1.076 1.076     1.084 1.073 1.081  
B3LYP 1.094 1.075 1.075 1.077 1.079 1.079   1.078   1.077 1.075 1.046 1.086 1.075    
B3LYPultrafine         1.079   1.079             1.075   1.075
B3PW91   1.076 1.076 1.077 1.080 1.079 1.079 1.079   1.078     1.086 1.076 1.084  
mPW1PW91   1.074   1.075 1.078 1.078 1.078 1.077 1.077 1.077     1.084   1.082  
M06-2X         1.047                      
PBEPBE   1.084     1.088 1.087 1.087 1.086 1.085 1.086 1.084   1.093 1.084    
PBEPBEultrafine         1.088                      
PBE1PBE         1.080                      
TPSSh         1.080   1.079             1.077    
Moller Plesset perturbation MP2   1.077 1.077 1.082 1.080 1.075 1.077 1.080 1.079 1.076   1.045 1.088      
MP2=FULL         1.080 1.074 1.075 1.079                
MP3         1.079   1.074                  
MP3=FULL         1.080   1.073                  
B2PLYP                           1.073    
B2PLYP=FULLultrafine         1.079                      
Configuration interaction CID         1.074                      
CISD         1.074                      
Quadratic configuration interaction QCISD   1.080     1.081       1.080              
Coupled Cluster CCD         1.081                      

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 1.075 1.067 1.071 1.064 1.064
density functional B1B95 1.084 1.087        
B3LYP 1.084 1.088 1.079 1.082 1.078 1.078
Moller Plesset perturbation MP2 1.091 1.089 1.085 1.082 1.084 1.084
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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