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

Geometry Comparison

C4H6 (Bicyclo[1.1.0]butane)


distance is atom 1 (C) to atom 9 (H)

Experimental bond length is 1.071  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.083
PM6 1.060
composite G2 1.070
G3 1.070
G3B3 1.082
G4 1.078
CBS-Q 1.072

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 1.076 1.061 1.061 1.065 1.070 1.070 1.070 1.070 1.069 1.069 1.067 1.068 1.077 1.067 1.075 1.067
density functional LSDA 1.093 1.083 1.083 1.086 1.090 1.089 1.090 1.088 1.087 1.086     1.096 1.085 1.093  
SVWN   1.083     1.090   1.090                  
BLYP 1.101 1.082 1.082 1.086 1.089 1.087 1.088 1.086 1.085 1.085     1.094 1.082 1.092  
B1B95             1.079                  
B3LYP 1.092 1.074 1.074 1.078 1.081 1.080 1.081 1.079   1.078 1.076 1.077 1.087 1.076 1.085 1.076
B3LYPultrafine                           1.076   1.076
B3PW91   1.074 1.074 1.077 1.081 1.081 1.081 1.080   1.079     1.087 1.077 1.085  
mPW1PW91   1.073   1.076 1.080 1.079 1.079 1.078 1.078 1.077     1.086 1.075 1.083  
M06-2X         1.079                      
PBEPBE   1.083     1.089 1.088 1.089 1.087 1.086 1.086 1.085   1.095 1.084   1.084
PBEPBEultrafine         1.089                      
PBE1PBE         1.081                      
HSEh1PBE         1.081                      
TPSSh         2.249   2.248             2.241    
Moller Plesset perturbation MP2   1.074 1.074 1.081 2.244 1.075 1.076 1.080 1.079 1.075   1.075 1.089 2.235 1.087  
MP2=FULL   1.074     2.242 1.074 1.075 1.079         1.088 2.227    
MP3         1.080   2.241                  
MP3=FULL         2.246   2.240                  
MP4         2.219                      
B2PLYP         1.079                 2.238    
B2PLYP=FULLultrafine         1.079                      
Configuration interaction CID         1.076                      
CISD         1.076                      
Quadratic configuration interaction QCISD   1.077     1.082     1.081 1.080              
Coupled Cluster CCD         1.082                      

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 1.071 1.077 1.068 1.073 1.064 1.064
density functional B1B95 1.085 1.089        
B3LYP 1.086 1.090 1.082 1.085 1.079 1.079
Moller Plesset perturbation MP2 1.094 1.091 1.086 1.082 1.086 1.085
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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