return to home page

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

Geometry Comparison

C2H2O2 (Ethanedial)


distance is atom 1 (C) to atom 2 (C)

Experimental bond length is 1.526  Å

Display Options
Switch to bar chart display
Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.518
PM6 1.543
composite G2 1.517
G3 1.517
G3B3 1.525
G4 1.529
CBS-Q 1.521

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 1.542 1.505 1.505 1.494 1.517 1.517 1.519 1.520 1.520 1.520 1.520 1.514 1.516 1.519 1.520 1.520
density functional LSDA 1.560 1.502 1.502 1.491 1.508 1.508 1.508 1.509 1.509 1.507     1.508 1.505 1.508  
SVWN   1.513     1.508   1.513                  
BLYP 1.596 1.535 1.535 1.520 1.538 1.538 1.539 1.540 1.540 1.539     1.538 1.535 1.540  
B1B95 1.562 1.513 1.513 1.501 1.518 1.519 1.520 1.520 1.520 1.520     1.518 1.516 1.518  
B3LYP 1.573 1.519 1.519 1.507 1.525 1.525 1.526 1.526   1.526 1.525 1.524 1.525 1.522 1.527 1.523
B3LYPultrafine         1.525   1.526             1.523   1.529
B3PW91   1.516 1.516 1.504 1.522 1.522 1.523 1.523   1.524     1.521 1.520 1.523  
mPW1PW91   1.512   1.500 1.519 1.519 1.520 1.520 1.521 1.522     1.518 1.517 1.520  
M06-2X         1.521                      
PBEPBE   1.527     1.531 1.531 1.531 1.533 1.531 1.532 1.531   1.531 1.530   1.530
PBEPBEultrafine         1.530                      
PBE1PBE         1.519                      
HSEh1PBE         1.519                      
TPSSh         1.526   1.527             1.522    
Moller Plesset perturbation MP2   1.521 1.521 1.510 1.514 1.514 1.514 1.522 1.522 1.517   1.521 1.524 1.514 1.524  
MP2=FULL   1.521     1.513 1.513 1.514 1.519         1.523      
MP3         1.515   1.516                  
MP3=FULL         1.516   1.517                  
MP4         1.523                      
B2PLYP         1.522                 1.519    
B2PLYP=FULLultrafine         1.519                      
Configuration interaction CID         1.514                      
CISD         1.515                      
Quadratic configuration interaction QCISD   1.529     1.523     1.528 1.529              
Coupled Cluster CCD         1.518                      
CCSD         1.519                      
CCSD(T)         1.519                      

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 1.524 1.537 1.517 1.533 1.508 1.508
density functional B1B95 1.538 1.546        
B3LYP 1.543 1.551 1.531 1.543 1.523 1.524
Moller Plesset perturbation MP2 1.552 1.543 1.537 1.534 1.534 1.534
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
Please use the error report form to report problems.