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

Geometry Comparison

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


distance is atom 1 (C) to atom 3 (C)

Experimental bond length is 1.530  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.525
PM6 1.525
composite G2 1.518
G3 1.329
G3B3 1.522
G4 1.523
CBS-Q 1.330

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 1.532 1.541 1.541 1.529 1.522 1.518 1.518 1.519 1.519 1.519 1.516 1.520 1.521 1.516 1.521 1.516
density functional LSDA 1.533 1.528 1.528 1.518 1.505 1.505 1.506 1.504 1.505 1.505     1.508 1.502 1.507  
SVWN   1.532     1.505   1.513                  
BLYP 1.561 1.553 1.553 1.544 1.531 1.532 1.532 1.531 1.532 1.532     1.534 1.355 1.534  
B1B95 1.536 1.535 1.535 1.525 1.510 1.512 1.512 1.511 1.511 1.512     1.513 1.508 1.512  
B3LYP 1.549 1.543 1.543 1.534 1.522 1.522 1.522 1.522   1.522 1.518 1.525 1.525 1.518    
B3LYPultrafine         1.522                     1.520
B3PW91   1.539 1.539 1.529 1.517 1.517 1.517 1.516   1.517     1.519 1.514 1.518  
mPW1PW91   1.537   1.527 1.514 1.514 1.514 1.514 1.514 1.515     1.516   1.516  
M06-2X         1.522                      
PBEPBE   1.545     1.522 1.522 1.522 1.521 1.522 1.522 1.519   1.524 1.519    
PBEPBEultrafine         1.522                      
PBE1PBE         1.514                      
HSEh1PBE         1.520                      
TPSSh         1.526   1.526             1.522    
Moller Plesset perturbation MP2   1.551 1.551 1.543 1.512 1.512 1.519 1.516 1.517     1.519 1.522 1.518    
MP2=FULL   1.551 1.551 1.542 1.511 1.510 1.511 1.515         1.521 1.512    
MP3         1.521   1.526                  
MP3=FULL         1.525   1.525                  
MP4       1.543                        
B2PLYP         1.524                 1.516    
B2PLYP=FULLultrafine         1.524                      
Configuration interaction CID         1.515                      
CISD         1.337                      
Quadratic configuration interaction QCISD   1.560 1.560 1.551 1.522 1.521 1.522 1.526         1.532      
Coupled Cluster CCD   1.559 1.559 1.550 1.521 1.520 1.521 1.525         1.531      

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 1.529 1.538 1.526 1.534 1.534
density functional B1B95 1.541 1.528        
B3LYP 1.550 1.537 1.546 1.534 1.540 1.540
Moller Plesset perturbation MP2 1.566 1.531 1.557 1.524 1.557 1.557
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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