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

Geometry Comparison

C3H4N2 (1H-Imidazole)


distance is atom 8 (C) to atom 9 (N)

Experimental bond length is 1.364  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.393
PM6 1.351
composite G3 1.349
G3B3 1.367
G4 1.364
CBS-Q 1.350

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 1.384 1.368 1.368 1.363 1.349 1.349 1.350 1.349 1.349 1.347 1.346 1.329 1.350 1.346 1.351 1.346
density functional LSDA 1.398 1.376 1.376 1.373 1.360 1.359 1.361 1.357 1.357 1.356     1.360 1.354 1.360  
BLYP 1.423 1.398 1.398 1.394 1.381 1.381 1.383 1.380 1.380 1.377     1.382 1.376 1.382  
B1B95 1.397 1.378 1.378 1.374 1.358 1.360 1.360 1.358 1.358 1.356     1.360 1.354 1.359  
B3LYP 1.407 1.384 1.384 1.381 1.367 1.367   1.366   1.364 1.363 1.333 1.368 1.363    
B3LYPultrafine         1.367   1.368             1.363   1.363
B3PW91   1.381 1.381 1.377 1.363 1.363 1.364 1.362   1.360     1.363 1.358 1.364  
mPW1PW91   1.378   1.374 1.360 1.360 1.361 1.359 1.359 1.357     1.361   1.361  
M06-2X         1.332                      
PBEPBE   1.391     1.373 1.373 1.375 1.372 1.372 1.370 1.369   1.374 1.369    
PBEPBEultrafine         1.374                      
PBE1PBE         1.360                      
TPSSh         1.369   1.369             1.364    
Moller Plesset perturbation MP2   1.394 1.394 1.392 1.366 1.366 1.369 1.366 1.366 1.362   1.333 1.370      
MP2=FULL         1.365 1.364 1.367 1.365                
MP3         1.364   1.366                  
MP3=FULL         1.365   1.366                  
B2PLYP                           1.362    
B2PLYP=FULLultrafine         1.367                      
Configuration interaction CID         1.355                      
CISD         1.356                      
Quadratic configuration interaction QCISD   1.395     1.366       1.366              
Coupled Cluster CCD         1.364                      

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 1.376 1.360 1.373 1.358 1.370 1.370
density functional B1B95 1.388 1.372        
B3LYP 1.397 1.380 1.394 1.378 1.387 1.388
Moller Plesset perturbation MP2 1.412 1.380 1.404 1.376 1.402 1.402
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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