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

Geometry Comparison

BeS (beryllium sulfide)


distance is atom 1 (Be) to atom 2 (S)

Experimental bond length is 1.742  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.652
PM6 1.736
composite G2 1.732
G3 1.732
G3B3 1.750
G4 1.745
CBS-Q 1.735

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 aug-cc-pVQZ cc-pV(T+d)Z
hartree fock HF   1.760 1.739 1.765 1.732 1.732 1.733 1.729 1.729 1.731 1.725 1.740 1.736   1.725   1.729 1.726 1.726
density functional LSDA 1.684 1.767 1.754 1.774 1.749 1.749 1.749 1.740 1.740 1.745     1.754 1.738   1.750      
SVWN   1.767     1.749   1.749                        
BLYP   1.785 1.771 1.792 1.767 1.767 1.767 1.759 1.759 1.763     1.770     1.768      
B1B95 1.678 1.765 1.750 1.772 1.743 1.746 1.745 1.739 1.739 1.743     1.750 1.736   1.747      
B3LYP 1.681 1.770 1.755 1.777 1.750 1.750 1.750 1.743   1.747 1.739 1.758 1.754   1.738   1.741 1.738 1.740
B3LYPultrafine         1.750                       1.740    
B3PW91   1.770 1.754 1.775 1.748 1.748 1.748 1.742   1.745           1.751      
mPW1PW91 1.663 1.767   1.772 1.745 1.745 1.744 1.739 1.739 1.742           1.748      
M06-2X         1.740                            
PBEPBE   1.782     1.762 1.762 1.762 1.756 1.756 1.759 1.751   1.767 1.754         1.752
PBEPBEultrafine         1.762                            
PBE1PBE         1.745                            
HSEh1PBE         1.746                            
TPSSh         1.749   1.749             1.743          
Moller Plesset perturbation MP2   1.794 1.769 1.800 1.754 1.754 1.754 1.753 1.753 1.759   1.773 1.771   1.752 1.776 1.761 1.753 1.757
MP2=FULL   1.794     1.750 1.750 1.751 1.751             1.744 1.773     1.746
MP3         1.740   1.740                        
MP3=FULL         1.737   1.737                        
MP4         1.770     1.768           1.771          
B2PLYP         1.754                 1.747          
Configuration interaction CID         1.739     1.737                      
CISD         1.744                            
Quadratic configuration interaction QCISD   1.804     1.757   1.757 1.755 1.755       1.772 1.754         1.752
QCISD(T)         1.765     1.764                      
Coupled Cluster CCD         1.743     1.742         1.759            
CCSD         1.748     1.747                      
CCSD(T)   1.801     1.760 1.760 1.760 1.759 1.759   1.757   1.777 1.761   1.780 1.762   1.760

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 1.770 1.744 1.765 1.731 1.769 1.738
density functional B1B95 1.793 1.770        
B3LYP 1.793 1.768 1.787 1.757 1.789 1.747
Moller Plesset perturbation MP2 1.821 1.774 1.803 1.761 1.805 1.763
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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