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

Geometry Comparison

C2Cl2 (dichloroacetylene)


distance is atom 1 (C) to atom 2 (C)

Experimental bond length is 1.246  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM6 1.374
composite G2 1.180
G3 1.180
G3B3 1.206
G4 1.202

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 cc-pV(T+d)Z
hartree fock HF 1.172 1.175 1.181 1.183 1.180 1.180 1.181 1.177 1.177 1.177 1.174 1.175 1.185 1.176 1.185 1.175 1.176
density functional LSDA 1.215 1.202 1.209 1.212 1.214 1.214 1.216 1.206 1.206 1.211     1.219 1.207 1.220    
SVWN   1.202     1.214   1.216                    
BLYP 1.222 1.208 1.214 1.217 1.218 1.218 1.220 1.211 1.211 1.214     1.223 1.210      
B1B95 1.205 1.195 1.201 1.204 1.203 1.205 1.206 1.199 1.199 1.202     1.209 1.197 1.208    
B3LYP 1.208 1.197 1.203 1.206 1.206 1.206 1.207 1.200   1.202 1.198 1.199 1.211 1.199 1.211 1.198 1.200
B3LYPultrafine         1.206                     1.198  
B3PW91   1.198 1.204 1.206 1.206 1.206 1.208 1.201   1.203     1.211 1.200      
mPW1PW91   1.195 1.202 1.204 1.204 1.204 1.205 1.199 1.199 1.201     1.208 1.198      
M06-2X         1.201                        
PBEPBE   1.209     1.219 1.219 1.220 1.213 1.213 1.216 1.212   1.223 1.212   1.212  
PBEPBEultrafine         1.219                        
PBE1PBE         1.205                        
HSEh1PBE         1.205                        
TPSSh         1.209   1.211             1.202      
Moller Plesset perturbation MP2   1.212 1.217 1.225 1.217 1.217 1.220 1.216 1.216 1.215   1.211 1.228 1.214 1.230   1.214
MP2=FULL   1.211 1.216 1.224 1.215 1.215 1.217 1.215         1.227 1.210 1.229   1.210
MP3         1.202   1.203                    
MP3=FULL         1.202   1.203                    
MP4   1.212     1.219                        
B2PLYP         1.209                 1.203      
Configuration interaction CID         1.194                        
CISD         1.195                        
Quadratic configuration interaction QCISD   1.206 1.210 1.218 1.208 1.208   1.206 1.206       1.218 1.202      
Coupled Cluster CCD   1.204 1.208 1.216 1.205 1.205   1.204         1.216        
CCSD         1.207                        
CCSD(T)         1.214                 1.209      

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 1.218 1.216 1.189 1.183 1.187 1.187
density functional B1B95 1.245 1.247        
B3LYP 1.244 1.245 1.217 1.212 1.214 1.215
Moller Plesset perturbation MP2 1.273 1.257 1.239 1.224 1.236 1.236
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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