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

Geometry Comparison

C5H8 (Cyclobutane, methylene-)


distance is atom 1 (C) to atom 6 (H)

Experimental bond length is 1.101  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.101
PM6 1.096
composite G3 3.791
G3B3 1.096
G4 1.094
CBS-Q 3.800

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 1.088 1.081 1.081 1.083 1.084 1.084 1.084 1.084 1.084 1.084 1.082 1.083 1.091 1.082 1.089 1.082
density functional LSDA 1.104 1.102 1.102 1.103 1.104 1.103 1.103 1.102 1.101 1.102     1.109 1.099 1.106  
SVWN   1.102     1.104   1.103                  
BLYP 1.113 1.101 1.101 1.103 1.103 1.102 1.102 1.100 1.099 1.101     1.109 1.096 1.105  
B1B95 1.102 1.091 1.091 1.093 1.092 1.092 1.093 1.091 1.090 1.091     1.098 1.087 1.095  
B3LYP 1.104 1.093 1.093 1.096 1.096 1.095 1.095 1.093   1.094 1.090 1.091 1.101 1.090 1.098  
B3LYPultrafine         1.096                     1.090
B3PW91   1.094 1.094 1.095 1.096 1.095 1.095 1.094   1.094     1.101 1.091 1.098  
mPW1PW91   1.092 1.092 1.093 1.094 1.093 1.093 1.092 1.091 1.092     1.099 1.089 1.096  
M06-2X         1.093                      
PBEPBE   1.102     1.104 1.102 1.103 1.101 1.101 1.102 1.099   1.109 1.099    
PBEPBEultrafine         1.104                      
PBE1PBE         1.095                      
HSEh1PBE         1.095                      
TPSSh         1.096   1.095             1.091    
Moller Plesset perturbation MP2   1.094 1.094 1.099 1.095 1.090 1.091 1.093 1.093 1.090   1.090 1.102 1.088 1.100  
MP2=FULL   1.093 1.093 1.099 1.095 1.089 1.089 1.093         1.101 1.084    
MP3         1.094   1.089                  
MP3=FULL         1.094   1.088                  
B2PLYP         1.094                 1.088    
B2PLYP=FULLultrafine         1.094                      
Configuration interaction CID   1.090     1.089                      
CISD   1.090     1.089                      
Quadratic configuration interaction QCISD   1.098 1.098 1.103 1.097 1.091 1.091 1.096         1.104      
Coupled Cluster CCD   1.097 1.097 1.102 1.096 1.090 1.090 1.095         1.103      

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 1.087 1.089 1.085 1.086 1.082 1.082
density functional B1B95 1.100 1.100        
B3LYP 1.102 1.102 1.097 1.097 1.096 1.096
Moller Plesset perturbation MP2 1.111 1.103 1.103 1.095 1.104 1.104
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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