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

Geometry Comparison

C5H8 (Cyclopentene)


distance is atom 2 (C) to atom 4 (C)

Experimental bond length is 1.518  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.495
PM6 1.515
composite G2 1.511
G3 2.351
G3B3 1.513
G4 1.513
CBS-Q 2.354

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 1.523 1.522 1.522 1.512 1.511 1.511 1.511 1.511 1.511 1.510 1.509 1.509 1.511 1.508 1.512 1.508
density functional LSDA 1.518 1.508 1.508 1.501 1.495 1.495 1.496 1.493 1.493 1.493     1.496 1.490 1.495  
SVWN   1.509     1.495   1.498                  
BLYP 1.547 1.535 1.535 1.528 1.522 1.522 1.524 1.521 1.521 1.520     1.523 1.517 1.522  
B1B95 1.524 1.518 1.518 1.509 1.503 1.503 1.504 1.502 1.502 1.502     1.503 1.499 1.502  
B3LYP 1.536 1.524 1.524 1.517 1.513 1.513 2.366 1.512   1.511 1.509 1.512 1.513 1.508    
B3LYPultrafine         1.513   1.514             1.510   1.510
B3PW91   1.521 1.521 1.513 1.508 1.507 1.508 1.506   1.506     1.507 2.351 1.508  
mPW1PW91   1.518 1.518 1.510 1.506 1.505 1.506 1.504 1.504 1.504     1.505 1.501 1.506  
M06-2X         1.511                      
PBEPBE   1.527     1.513 1.513 1.514 1.511 1.512 1.512 1.509   1.513 1.509    
PBEPBEultrafine         1.516                      
PBE1PBE         1.505                      
HSEh1PBE         1.507                      
TPSSh         1.514   1.514             1.509    
Moller Plesset perturbation MP2   1.534 1.534 1.528 1.509 1.508 1.509 1.512 1.512 1.508   1.507 1.516 2.357    
MP2=FULL   1.534 1.534 1.528 1.507 1.506 1.508 1.510         1.514 2.347    
MP3         1.513   2.363                  
MP3=FULL         1.512   1.512                  
MP4       1.528                        
B2PLYP         1.512                 1.507    
B2PLYP=FULLultrafine         1.512                      
Configuration interaction CID         2.350                      
CISD         2.351                      
Quadratic configuration interaction QCISD   1.540 1.540 1.533 1.514 1.513 1.515 1.517 1.518       1.522      
Coupled Cluster CCD   1.538 1.538 1.532 1.513 1.512 1.514 1.516         1.521      

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 1.529 1.525 1.525 1.520 1.519 1.518
density functional B1B95 1.529 1.522        
B3LYP 1.538 1.530 1.531 1.525 1.523 1.523
Moller Plesset perturbation MP2 1.555 1.529 1.545 1.521 1.542 1.542
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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