return to home page

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

Geometry Comparison

NH2CONH2 (Urea)


distance is atom 4 (N) to atom 8 (H)

Experimental bond length is 0.998  Å

Display Options
Switch to bar chart display
Calculated bond length in Å
Methods with predefined basis sets
semi-empirical AM1 0.984
PM3 0.995
PM6 1.000
composite G2 0.994
G3 0.994
G3B3 1.010
G4 1.007
CBS-Q 0.993

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 1.027 0.994 0.994 0.989 0.994 0.991 0.992 0.990 0.992 0.991 0.992 0.991 0.998 0.989 0.994 0.989
density functional LSDA 1.048 1.019 1.019 1.015 1.018 1.016 1.016 1.014 1.014 1.014   1.013 1.021 1.013 1.016 1.013
SVWN   1.019     1.018 1.016 1.016 1.014 1.014 1.014     1.021 1.013 1.016 1.013
BLYP 1.067 1.020 1.020 1.015 1.020 1.018 1.017 1.016 1.016 1.016   1.014 1.024 1.014 1.020  
B1B95 1.045 1.007 1.007 1.002 1.006 1.006 1.004 1.003 1.003 1.003   1.002 1.010 1.001 1.005 1.001
B3LYP 1.052 1.011 1.011 1.006 1.011 1.008 1.008 1.007 1.007 1.007 1.007 1.005 1.014 1.005 1.009 1.004
B3LYPultrafine         1.011             1.005 1.014 1.005 1.009 1.004
B3PW91 1.049 1.010 1.010 1.005 1.009 1.007 1.007 1.006 1.006 1.006   1.005 1.013 1.004 1.011  
mPW1PW91 1.046 1.008 1.008 1.003 1.007 1.005 1.005 1.004 1.004 1.004   1.003 1.011 1.002 1.006 1.002
M06-2X 1.043 1.010 1.010 1.005 1.009 1.006 1.007 1.006 1.006 1.005   1.005 1.012 1.004 1.008 1.003
PBEPBE 1.061 1.019 1.019 1.014 1.019 1.017 1.016 1.015 1.015 1.015 1.015 1.014 1.022 1.014 1.017 1.013
PBEPBEultrafine         1.019             1.014 1.022 1.014 1.017 1.013
PBE1PBE 1.046 1.009 1.009 1.004 1.008 1.008 1.006 1.005 1.005 1.005   1.004 1.012 1.004 1.007 1.003
HSEh1PBE 1.047 1.009 1.009 1.004 1.008 1.006 1.006 1.005 1.005 1.005   1.004 1.012 1.003 1.007 1.003
TPSSh   1.013 1.013 1.007 1.012 1.010 1.010 1.009       1.008 1.016 1.007 1.011 1.007
Moller Plesset perturbation MP2 1.054 1.009 1.009 1.008 1.011 1.006 1.007 1.006 1.007 1.005   1.006 1.015 1.004 1.012 1.004
MP2=FULL 1.054 1.009 1.009 1.008 1.011 1.005 1.006 1.005 1.007 1.003   1.006 1.014 1.001 1.011 1.001
MP3         1.009   1.004         1.004 1.013 1.001    
MP3=FULL         1.009   1.003         1.003 1.012 0.998    
MP4   1.012     1.014       1.010     1.009 1.018 1.006 1.015 1.007
MP4=FULL   1.012     1.016       1.009       1.017 1.004 1.014 1.004
B2PLYP=FULLultrafine         1.011                      
Configuration interaction CID   1.004 1.004 1.002 1.003     0.998                
CISD 1.055 1.004 1.004 1.002 1.003     0.998                
Quadratic configuration interaction QCISD   1.014 1.014 1.010 1.014 1.008 1.009 1.009 1.010 1.007   1.008 1.018 1.005 1.012 1.004
QCISD(T)         1.014             1.009 1.018 1.006 1.015 1.009
Coupled Cluster CCD   1.009 1.009 1.008 1.011 1.005 1.006 1.006 1.007 1.004   1.005 1.015 1.002 1.011 1.002
CCSD         1.014             1.008 1.018 1.005 1.012 1.005
CCSD=FULL         1.012             1.006 1.015 1.000 1.011 1.000
CCSD(T)         1.014             1.009 1.018 1.006 1.015 1.006
CCSD(T)=FULL         1.014             1.008 1.017 1.003 1.014 1.003

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 0.995 1.000 0.991 0.996 0.991 0.991
density functional B1B95 1.011 1.016        
B3LYP 1.014 1.018 1.009 1.014 1.009 1.009
Moller Plesset perturbation MP2 1.017 1.019 1.011 1.014 1.013 1.013
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
Please use the error report form to report problems.