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

Geometry Comparison

KF (Potassium Fluoride)


distance is atom 1 (K) to atom 2 (F)

Experimental bond length is 2.171  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM6 1.895
composite G2 2.185
G3B3 2.106
G4 2.127

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
hartree fock HF   2.218 2.138 2.250 2.185 2.185 2.258 2.177 2.177 2.160 2.207 2.297
density functional LSDA 2.246 2.215 2.097 2.231 2.131 2.131 2.205 2.077 2.077 2.085    
SVWN   2.215     2.131   2.205          
BLYP   2.310 2.158 2.308 2.199 2.199 2.275 2.146 2.146 2.147    
B1B95         2.166              
B3LYP   2.263 2.134 2.269 2.174 2.174 2.254 2.136 2.136 2.132   2.305
B3LYPultrafine         2.174              
B3PW91   2.253 2.133 2.261 2.169 2.169 2.247 2.130 2.130 2.128    
mPW1PW91   2.241 2.126   2.165 2.165 2.242 2.129 2.129 2.124    
M06-2X         2.162              
PBEPBE   2.292 2.147 2.294 2.186 2.186 2.261 2.131 2.131 2.135    
PBEPBEultrafine         2.185              
PBE1PBE         2.163              
HSEh1PBE         2.164              
TPSSh         2.175   2.247          
Moller Plesset perturbation MP2   2.278 2.165 2.276 2.179 2.178 2.273 2.161 2.161 2.127   2.350
MP2=FULL   2.256 2.146 2.276 2.179 2.178 2.272 2.160 2.160 2.126    
MP3         2.175   2.176          
MP3=FULL         2.175   2.259          
MP4   2.316     2.180              
B2PLYP         2.173              
Configuration interaction CID   2.259 2.159 2.267 2.177     2.165        
CISD   2.269 2.163 2.271 2.177     2.165        
Quadratic configuration interaction QCISD   2.291 2.170 2.279 2.179 2.179 2.267 2.168        
QCISD(T)         2.177              
Coupled Cluster CCD   2.262 2.160 2.269 2.176 2.176 2.262 2.165        
CCSD         2.177              
CCSD(T)         2.177              
CCSD(T)=FULL         2.177              

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 2.213   2.218   2.274 2.285
density functional B1B95 2.211          
B3LYP 2.214   2.221   2.272 2.294
Moller Plesset perturbation MP2 2.237   2.242   2.294 2.312
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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