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

Geometry Comparison

KCl (Potassium Chloride)


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

Experimental bond length is 2.667  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM6 2.750
composite G2 2.771
G3B3 2.675
G4 2.676

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
hartree fock HF   2.829 2.787 2.845 2.771 2.771 2.787 2.754 2.754 2.743 2.746 2.831
density functional LSDA 2.631 2.731 2.681 2.758 2.667 2.667 2.683 2.613 2.613 2.622    
SVWN   2.731     2.667   2.683          
BLYP   2.813 2.759 2.836 2.748 2.748 2.769 2.705 2.705 2.707    
B1B95         2.717              
B3LYP   2.795 2.746 2.817 2.732 2.732 2.751 2.696 2.696 2.694   2.807
B3LYPultrafine         2.730              
B3PW91   2.790 2.744 2.810 2.724 2.724 2.740 2.684 2.684 2.685    
mPW1PW91   2.783 2.738   2.719 2.719 2.735 2.680 2.680 2.680    
M06-2X         2.705              
PBEPBE   2.793 2.742 2.816 2.727 2.727 2.745 2.678 2.678 2.685    
PBEPBEultrafine         2.726              
PBE1PBE         2.716              
HSEh1PBE         2.716              
TPSSh         2.731   2.745          
Moller Plesset perturbation MP2   2.874 2.876 2.862 2.750 2.741 2.762 2.698 2.698 2.691   2.892
MP2=FULL   2.844 2.783 2.861 2.750 2.741 2.761 2.695 2.695 2.689    
MP3         2.741   2.751          
MP3=FULL         2.751   2.768          
MP4   2.882     2.742              
B2PLYP         2.731              
Configuration interaction CID   2.877 2.883 2.861 2.744     2.710        
CISD   2.879 2.884 2.862 2.744     2.710        
Quadratic configuration interaction QCISD   2.882 2.890 2.865 2.743 2.743 2.763 2.706        
QCISD(T)         2.743              
Coupled Cluster CCD   2.880 2.889 2.863 2.743 2.743 2.762 2.705        
CCSD         2.743              
CCSD(T)         2.743              
CCSD(T)=FULL         2.743              

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 2.885   2.891   2.813 2.812
density functional B1B95 2.882          
B3LYP 2.884   2.886   2.790 2.790
Moller Plesset perturbation MP2 2.896   2.903   2.821 2.821
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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