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

Geometry Comparison

C2H2O2 (Ethanedial)


distance is atom 1 (C) to atom 3 (H)

Experimental bond length is 1.132  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.101
PM6 1.104
composite G2 1.091
G3 1.091
G3B3 1.109
G4 1.110
CBS-Q 1.095

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 1.103 1.082 1.082 1.081 1.091 1.092 1.092 1.093 1.094 1.094 1.092 1.088 1.100 1.092 1.098 1.091
density functional LSDA 1.131 1.119 1.119 1.115 1.123 1.123 1.122 1.123 1.123 1.124     1.132 1.121 1.127  
SVWN   1.118     1.123   1.121                  
BLYP 1.139 1.114 1.114 1.112 1.120 1.120 1.117 1.119 1.118 1.120     1.129 1.115 1.123  
B1B95 1.124 1.101 1.101 1.099 1.106 1.107 1.106 1.107 1.107 1.108     1.116 1.104 1.110  
B3LYP 1.127 1.103 1.103 1.101 1.109 1.109 1.108 1.109   1.110 1.106 1.106 1.119 1.106 1.113 1.105
B3LYPultrafine         1.109   1.108             1.106   1.106
B3PW91   1.103 1.103 1.101 1.109 1.109 1.108 1.109   1.111     1.118 1.107 1.114  
mPW1PW91   1.101   1.099 1.107 1.107 1.106 1.107 1.107 1.109     1.116 1.105 1.112  
M06-2X         1.106                      
PBEPBE   1.116     1.121 1.121 1.119 1.121 1.120 1.122 1.118   1.130 1.118   1.117
PBEPBEultrafine         1.121                      
PBE1PBE         1.109                      
HSEh1PBE         1.108                      
TPSSh         1.109   1.108             1.107    
Moller Plesset perturbation MP2   1.100 1.100 1.102 1.105 1.101 1.100 1.106 1.107 1.105   1.103 1.117 1.101 1.113  
MP2=FULL   1.100     1.105 1.100 1.099 1.106         1.116      
MP3         1.103   1.099                  
MP3=FULL         1.104   1.098                  
MP4         1.110                      
B2PLYP         1.106                 1.103    
B2PLYP=FULLultrafine         1.106                      
Configuration interaction CID         1.098                      
CISD         1.098                      
Quadratic configuration interaction QCISD   1.104     1.107     1.108 1.107              
Coupled Cluster CCD         1.106                      
CCSD         1.106                      
CCSD(T)         1.109                      

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 1.088 1.096 1.086 1.094 1.083 1.083
density functional B1B95 1.110 1.116        
B3LYP 1.111 1.117 1.105 1.111 1.105 1.105
Moller Plesset perturbation MP2 1.114 1.114 1.106 1.106 1.107 1.107
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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