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

Geometry Comparison

C3H4N2 (1H-Imidazole)


distance is atom 3 (C) to atom 9 (N)

Experimental bond length is 1.377  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.403
PM6 1.336
composite G3 1.372
G3B3 1.381
G4 1.380
CBS-Q 1.373

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 1.391 1.385 1.385 1.381 1.372 1.372 1.372 1.373 1.372 1.371 1.369 1.328 1.373 1.370 1.374 1.370
density functional LSDA 1.400 1.384 1.384 1.381 1.368 1.368 1.369 1.366 1.366 1.365     1.368 1.363 1.368  
BLYP 1.427 1.408 1.408 1.405 1.393 1.392 1.394 1.391 1.391 1.389     1.392 1.388 1.393  
B1B95 1.402 1.389 1.389 1.384 1.371 1.372 1.373 1.371 1.371 1.369     1.371 1.367 1.371  
B3LYP 1.412 1.395 1.395 1.392 1.381 1.380   1.380   1.378 1.376 1.326 1.380 1.376    
B3LYPultrafine         1.381   1.381             1.379   1.380
B3PW91   1.391 1.391 1.387 1.375 1.375 1.376 1.375   1.373     1.376 1.372 1.376  
mPW1PW91   1.389   1.385 1.373 1.373 1.374 1.372 1.372 1.371     1.373   1.374  
M06-2X         1.325                      
PBEPBE   1.400     1.384 1.384 1.385 1.382 1.383 1.381 1.380   1.384 1.380    
PBEPBEultrafine         1.386                      
PBE1PBE         1.373                      
TPSSh         1.383   1.384             1.379    
Moller Plesset perturbation MP2   1.405 1.405 1.402 1.376 1.375 1.381 1.375 1.375 1.371   1.325 1.378      
MP2=FULL         1.374 1.374 1.376 1.373                
MP3         1.379   1.380                  
MP3=FULL         1.379   1.381                  
B2PLYP                           1.376    
B2PLYP=FULLultrafine         1.382                      
Configuration interaction CID         1.372                      
CISD         1.373                      
Quadratic configuration interaction QCISD   1.409     1.383       1.382              
Coupled Cluster CCD         1.378                      

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 1.393 1.382 1.392 1.381 1.387 1.387
density functional B1B95 1.398 1.383        
B3LYP 1.408 1.393 1.406 1.392 1.397 1.398
Moller Plesset perturbation MP2 1.422 1.389 1.415 1.386 1.412 1.412
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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