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

Geometry Comparison

SiN (Silicon nitride)


distance is atom 1 (Si) to atom 2 (N)

Experimental bond length is 1.575  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 1.472
PM6 1.498
composite G2 1.589
G3 1.589
G3B3 1.578
G4 1.571
CBS-Q 1.590

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 cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pV(T+d)Z
hartree fock HF   1.765 1.610 1.804 1.589 1.589 1.589 1.586 1.586 1.576 1.571 1.606 1.620 1.586 1.576 1.623 1.586 1.576 1.575
ROHF   1.589 1.544   1.540 1.540 1.543 1.537         1.554 1.540          
density functional LSDA 1.565 1.624 1.580 1.626 1.574 1.574 1.575 1.570 1.570 1.565     1.585 1.569   1.588      
SVWN   1.624     1.574   1.575                        
BLYP   1.642 1.599 1.647 1.594 1.594 1.595 1.590 1.589 1.584     1.604 1.589   1.607      
B1B95 1.556 1.623 1.578 1.627 1.570 1.572 1.573 1.568 1.568 1.564     1.584 1.568   1.586      
B3LYP 1.561 1.628 1.583 1.632 1.578 1.578 1.579 1.574   1.568 1.566 1.582 1.589 1.573 1.567 1.592 1.574 1.568 1.566
B3LYPultrafine         1.578                       1.576    
B3PW91   1.627 1.582 1.630 1.575 1.575 1.576 1.571   1.567     1.587 1.571   1.590      
mPW1PW91 1.531 1.625   1.628 1.572 1.572 1.573 1.568 1.568 1.564     1.584 1.569   1.587      
M06-2X         1.568                            
PBEPBE   1.640     1.590 1.590 1.591 1.586 1.586 1.581 1.578   1.601 1.585     1.586   1.579
PBEPBEultrafine         1.590                            
PBE1PBE         1.573                            
HSEh1PBE         1.573                            
TPSSh         1.581   1.582             1.578          
Moller Plesset perturbation MP2   1.587 1.541 1.588 1.537 1.537 1.539 1.532 1.532 1.529   1.540 1.548 1.532 1.525 1.551 1.533 1.526 1.527
MP2=FULL   1.587     1.536 1.536 1.538 1.531         1.547   1.521 1.550     1.524
MP3         1.544   1.542                        
MP3=FULL         1.542   1.542                        
MP4         1.550     1.544           1.545          
B2PLYP         1.577                 1.575          
Configuration interaction CID         1.546     1.541                      
CISD         1.562                            
Quadratic configuration interaction QCISD   1.655     1.585   1.586 1.579 1.579       1.601 1.579         1.572
QCISD(T)         1.591     1.584                      
Coupled Cluster CCD               1.539         1.558            
CCSD         1.583                            
CCSD(T)   1.651     1.586 1.586 1.587 1.579 1.579   1.573     1.581         1.575

Calculated bond length in Å
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
density functional B1B95 1.630 1.587        
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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