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

Geometry Comparison

C3H3NO (Oxazole)


distance is atom 1 (O) to atom 5 (C)

Experimental bond length is 1.357  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.372
PM6 1.399
composite G3 1.329
G3B3 1.357
G4 1.348
CBS-Q 1.327

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 1.372 1.374 1.374 1.363 1.329 1.329 1.329 1.327 1.327 1.325 1.324 1.329 1.329 1.325 1.331 1.325
density functional LSDA 1.406 1.397 1.397 1.388 1.349 1.349 1.350 1.347 1.347 1.344     1.349 1.346 1.351  
SVWN   1.383     1.349   1.352                  
BLYP 1.436 1.429 1.429 1.420 1.378 1.378 1.380 1.377 1.378 1.372     1.378 1.376 1.380  
B1B95 1.400 1.396 1.396 1.386 1.346 1.348 1.349 1.346 1.346 1.344     1.348 1.343 1.347  
B3LYP 1.412 1.404 1.404 1.396 1.357 1.358 1.359 1.356   1.353 1.353 1.356 1.358 1.355    
B3LYPultrafine         1.357   1.359             1.348   1.348
B3PW91   1.399 1.399 1.390 1.352 1.352 1.353 1.350   1.348     1.352 1.349 1.354  
mPW1PW91   1.395   1.385 1.348 1.348 1.349 1.346 1.346 1.344     1.348   1.350  
M06-2X         1.349                      
PBEPBE   1.420     1.368 1.368 1.369 1.366 1.367 1.363 1.363   1.368 1.365    
PBEPBEultrafine         1.359                      
PBE1PBE         1.348                      
HSEh1PBE         1.350                      
TPSSh         1.354   1.354             1.350    
Moller Plesset perturbation MP2   1.421 1.421 1.418 1.361 1.361 1.357 1.355 1.355 1.351   1.357 1.360 1.349    
MP2=FULL         1.360 1.360 1.362 1.354           1.346    
MP3         1.354   1.351                  
MP3=FULL         1.350   1.350                  
B2PLYP         1.359                 1.355    
B2PLYP=FULLultrafine         1.353                      
Configuration interaction CID         1.342                      
CISD         1.343                      
Quadratic configuration interaction QCISD   1.420             1.354              
Coupled Cluster CCD         1.356                      

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 1.371 1.337 1.370 1.337 1.366 1.366
density functional B1B95 1.394 1.356        
B3LYP 1.408 1.369 1.406 1.369 1.399 1.399
Moller Plesset perturbation MP2 1.432 1.371 1.428 1.371 1.427 1.427
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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