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

Geometry Comparison

C5H6 (Bicyclo[2.1.0]pent-2-ene)


distance is atom 3 (C) to atom 5 (C)

Experimental bond length is 1.560  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.509
PM6 1.525
composite G2 1.507
G3 2.288
G3B3 1.520
G4 1.516
CBS-Q 2.291

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 1.514 1.528 1.528 1.519 1.505 1.507 1.508 1.508 1.508 1.507 1.505 1.504 1.510 1.505 1.511 1.505
density functional LSDA 1.533 1.527 1.527 1.521 1.507 1.507 1.508 1.504 1.505 1.506     1.510 1.501 1.510  
SVWN   1.518     1.507   1.505                  
BLYP 1.560 1.556 1.556 1.548 1.534 1.534 1.536 1.532 1.533 1.533     1.536 2.307 1.537  
B1B95 1.532 1.533 1.533 1.524 1.509 1.510 1.511 1.509 1.509 1.509     1.511 1.505 1.511  
B3LYP 1.543 1.541 1.541 1.533 1.520 1.520 1.522 1.519   1.519 1.515 1.512 1.522 1.515    
B3LYPultrafine         1.520                     1.513
B3PW91   1.537 1.537 1.529 1.515 1.515 1.516 1.514   1.514     1.517 1.510 1.518  
mPW1PW91   1.534   1.526 1.512 1.512 1.514 1.512 1.512 1.512     1.514   1.515  
M06-2X         1.509                      
PBEPBE   1.548     1.525 1.525 1.526 1.523 1.523 1.524 1.520   1.526 1.520    
PBEPBEultrafine         1.525                      
PBE1PBE         1.512                      
HSEh1PBE         1.509                      
TPSSh         1.515   1.516             1.511    
Moller Plesset perturbation MP2   1.548 1.548 1.543 1.515 1.514 1.512 1.520 1.520     1.510 1.526 1.510    
MP2=FULL   1.548 1.548 1.542 1.513 1.512 1.515 1.518         1.525 1.504    
MP3         1.515   1.512                  
MP3=FULL         1.511   1.512                  
MP4       1.543                        
B2PLYP         1.513                 1.515    
B2PLYP=FULLultrafine         1.513                      
Configuration interaction CID         1.507                      
CISD         2.290                      
Quadratic configuration interaction QCISD   1.552 1.552 1.545 1.516 1.516 1.518 1.521         1.527      
Coupled Cluster CCD   1.549 1.549 1.543 1.515 1.514 1.516 1.520         1.526      

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 1.540 1.524 1.536 1.518 1.531 1.531
density functional B1B95 1.549 1.531        
B3LYP 1.561 1.542 1.555 1.535 1.548 1.548
Moller Plesset perturbation MP2 1.578 1.541 1.568 1.532 1.568 1.568
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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