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

Geometry Comparison

ClCN (chlorocyanogen)


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

Experimental bond length is 1.629  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.580
PM6 1.624
composite G2 1.640
G3 1.640
G3B3 1.646
G4 1.637
CBS-Q 1.641

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 cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z cc-pCVTZ
hartree fock HF 1.704 1.691 1.633 1.691 1.640 1.640 1.639 1.638 1.638 1.633 1.630 1.643 1.643 1.634 1.633 1.643 1.635 1.631  
density functional LSDA 1.711 1.682 1.622 1.684 1.626 1.626 1.625 1.621 1.621 1.615     1.629 1.616   1.629      
SVWN   1.682     1.626   1.625                        
BLYP 1.750 1.721 1.655 1.723 1.659 1.659 1.658 1.656 1.656 1.647     1.662 1.649   1.663      
B1B95 1.717 1.691 1.629 1.691 1.632 1.633 1.632 1.630 1.630 1.625     1.636 1.625   1.635      
B3LYP 1.730 1.703 1.641 1.704 1.646 1.646 1.645 1.643   1.635 1.631 1.645 1.648 1.637   1.649 1.637 1.632  
B3LYPultrafine         1.646                       1.638    
B3PW91   1.694 1.633 1.695 1.637 1.637 1.636 1.633   1.628     1.639 1.629   1.640      
mPW1PW91   1.690   1.691 1.634 1.634 1.633 1.631 1.631 1.625     1.637 1.627   1.637      
M06-2X         1.641                            
PBEPBE   1.706     1.645 1.645 1.644 1.642 1.642 1.635 1.630   1.648 1.637     1.637 1.631  
PBEPBEultrafine         1.645                            
PBE1PBE         1.634                            
HSEh1PBE         1.634                            
TPSSh         1.642   1.641             1.635          
Moller Plesset perturbation MP2   1.728 1.648 1.730 1.639 1.638 1.637 1.635 1.635     1.641 1.648 1.634   1.650   1.627  
MP2=FULL   1.729     1.637 1.636 1.634 1.634         1.646 1.630   1.648   1.622  
MP3         1.643   1.643                        
MP3=FULL         1.641   1.641                        
MP4         1.649                 1.643          
B2PLYP         1.643                 1.637          
Configuration interaction CID         1.640                            
CISD         1.642                            
Quadratic configuration interaction QCISD   1.737     1.649   1.647 1.646 1.646       1.659 1.642       1.638  
QCISD(T)         1.651                            
Coupled Cluster CCD         1.646               1.656            
CCSD         1.648                            
CCSD(T)   1.740     1.651 1.651 1.650   1.648         1.644       1.640  
CCSD(T)=FULL         1.648               1.658 1.638         1.636

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 1.695 1.653 1.692 1.652 1.677 1.684
density functional B1B95 1.707 1.654        
B3LYP 1.719 1.663 1.717 1.662 1.697 1.700
Moller Plesset perturbation MP2 1.740 1.658 1.737 1.656 1.720 1.729
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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