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

Geometry Comparison

C4H4N2 (1,3-Diazine)


distance is atom 3 (C) to atom 5 (N)

Experimental bond length is 1.350  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.354
PM6 1.364
composite G2 1.321
G3 1.321
G3B3 1.339
G4 1.334

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 1.354 1.332 1.332 1.333 1.316 1.321 1.316 1.319 1.319 1.318 1.317 1.313 1.322 1.317 1.323 1.317
density functional LSDA 1.385 1.346 1.346 1.347 1.333 1.333 1.333 1.328 1.329 1.329     1.334 1.326 1.333  
SVWN   1.338     1.333   1.329                  
BLYP 1.411 1.367   1.367 1.352 1.352 1.353   1.349 1.348     1.353 1.346 1.353  
B1B95 1.382 1.348 1.348 1.348 1.332 1.333 1.334 1.330 1.330 1.330     1.334 1.326 1.332  
B3LYP 1.391 1.352 1.352 1.354 1.339 1.339 1.340 1.336   1.335 1.333 1.329 1.340 1.333    
B3LYPultrafine         1.339   1.340             1.328   1.332
B3PW91   1.351 1.351 1.351 1.336 1.336   1.333   1.333     1.337 1.330 1.337  
mPW1PW91   1.348   1.348 1.333 1.333 1.334 1.330 1.331 1.331     1.334   1.334  
M06-2X         1.329                      
PBEPBE   1.363     1.347 1.347 1.348 1.344 1.344 1.344 1.341   1.347 1.341    
PBEPBEultrafine         1.339                      
PBE1PBE         1.334                      
HSEh1PBE         1.328                      
TPSSh         1.340   1.341             1.334    
Moller Plesset perturbation MP2   1.370 1.370 1.372 1.344 1.343 1.338 1.342 1.342 1.339   1.333 1.348 1.338    
MP2=FULL         1.342     1.341                
MP3         1.339   1.338                  
MP3=FULL         1.337   1.338                  
B2PLYP         1.334                 1.335    
B2PLYP=FULLultrafine         1.334                      
Quadratic configuration interaction QCISD                 1.340              

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 1.347 1.331 1.345 1.327 1.339 1.339
density functional B1B95 1.363 1.345        
B3LYP 1.370 1.351 1.367 1.347 1.359 1.360
Moller Plesset perturbation MP2 1.393 1.357 1.387 1.353 1.383 1.383
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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