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

Geometry Comparison

C3H3NO (Oxazole)


distance is atom 1 (O) to atom 7 (C)

Experimental bond length is 1.370  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.381
PM6 1.402
composite G3 1.355
G3B3 1.372
G4 1.367
CBS-Q 1.353

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 1.379 1.390 1.390 1.383 1.355 1.355 1.355 1.353 1.353 1.352 1.351 1.354 1.354 1.352 1.358 1.353
density functional LSDA 1.403 1.395 1.395 1.390 1.357 1.357 1.358 1.355 1.355 1.352     1.356 1.354 1.358  
SVWN   1.395     1.357   1.362                  
BLYP 1.435 1.427 1.427 1.423 1.388 1.388 1.390 1.387 1.387 1.383     1.387 1.386 1.389  
B1B95 1.402 1.401 1.401 1.394 1.360 1.361 1.362 1.360 1.360 1.358     1.360 1.357 1.361  
B3LYP 1.413 1.409 1.409 1.404 1.372 1.372 1.373 1.370   1.367 1.367 1.371 1.371 1.369    
B3LYPultrafine         1.372   1.373             1.368   1.369
B3PW91   1.404 1.404 1.398 1.365 1.365 1.366 1.364   1.362     1.364 1.362 1.367  
mPW1PW91   1.401   1.394 1.362 1.362 1.362 1.360 1.360 1.359     1.361   1.364  
M06-2X         1.363                      
PBEPBE   1.417     1.378 1.377 1.379 1.376 1.376 1.374 1.373   1.376 1.375    
PBEPBEultrafine         1.375                      
PBE1PBE         1.361                      
HSEh1PBE         1.363                      
TPSSh         1.371   1.372             1.369    
Moller Plesset perturbation MP2   1.423 1.423 1.422 1.371 1.370 1.372 1.364 1.363 1.362   1.368 1.368 1.365    
MP2=FULL         1.370 1.369 1.371 1.362           1.361    
MP3         1.370   1.368                  
MP3=FULL         1.368   1.369                  
B2PLYP         1.372                 1.369    
B2PLYP=FULLultrafine         1.370                      
Configuration interaction CID         1.361                      
CISD         1.363                      
Quadratic configuration interaction QCISD   1.426             1.371              
Coupled Cluster CCD         1.371                      

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 1.389 1.362 1.390 1.363 1.386 1.386
density functional B1B95 1.399 1.368        
B3LYP 1.414 1.382 1.414 1.383 1.406 1.406
Moller Plesset perturbation MP2 1.435 1.380 1.432 1.380 1.430 1.430
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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