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

Geometry Comparison

C2H4F2 (1,2-difluoroethane)


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

Experimental bond length is 1.493  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM6 1.550
composite G2 1.504
G3 1.504
G3B3 1.509
G4 1.512
CBS-Q 1.506

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* TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ
hartree fock HF   1.507 1.507 1.497 1.504 1.503 1.503 1.501 1.503 1.501 1.502 1.502 1.503 1.502
density functional LSDA 1.589 1.509 1.509                      
BLYP   1.529 1.529 1.516 1.521 1.520 1.517 1.515   1.519 1.512      
B1B95   1.508 1.508 1.498 1.503 1.502 1.501 1.498   1.499 1.497   1.499  
B3LYP   1.515 1.515 1.505 1.510 1.509 1.507 1.505 1.504 1.507 1.503 1.503 1.506 1.503
B3LYPultrafine         1.510                 1.521
B3PW91   1.512 1.512 1.502 1.506 1.506 1.504 1.501   1.504 1.500      
mPW1PW91   1.509 1.509 1.499 1.504 1.503 1.502 1.499   1.501 1.498      
PBEPBE   1.521 1.521 1.508 1.513 1.512 1.510 1.507   1.510 1.506   1.508  
PBEPBEultrafine         1.513                  
TPSSh         1.514   1.515       1.510      
Moller Plesset perturbation MP2   1.520 1.520 1.513 1.503 1.502 1.501 1.503 1.501 1.508 1.499   1.507 1.499
MP2=FULL   1.519 1.519 1.512 1.501 1.500 1.499 1.501   1.507 1.492      
MP3         1.505   1.506              
MP3=FULL         1.506   1.507              
MP4   1.527     1.507                  
B2PLYP                     1.504      
Configuration interaction CID   1.517 1.517 1.510 1.501     1.500            
CISD   1.517 1.517 1.510 1.501     1.500            
Quadratic configuration interaction QCISD   1.526 1.526 1.518 1.506 1.505 1.505 1.507   1.512 1.503      
QCISD(T)   1.527     1.507         1.514        
Coupled Cluster CCD   1.524 1.524 1.517 1.506 1.505 1.505 1.507   1.512 1.503      
CCSD   1.525     1.506         1.512        
CCSD(T)   1.527     1.507         1.514        
CCSD(T)=FULL         1.506                  

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 1.520   1.514   1.507 1.507
density functional B3LYP 1.531   1.521   1.514 1.514
Moller Plesset perturbation MP2 1.542   1.531   1.528 1.527
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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