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Relative enthalpies of isomers - Comparison of 298.15K enthalpies (kJ mol-1)

Isomers of C2H4N2

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a NH2CH2CN 540614 Aminoacetonitrile   sketch of Aminoacetonitrile
b NH2CCNH2 4403547 Diaminoacetylene   sketch of Diaminoacetylene
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
semi-empirical AM1
541.5 b
PM3
574.6 b
PM6
543.0 b
composite G1 NC
NC
G2MP2 NC
NC
G2 NC
NC
G3 NC
NC
G3B3 NC
NC
G4 NC
NC
CBS-Q NC
NC

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 daug-cc-pVTZ
hartree fock HF NC NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
ROHF  
NC
                             
density functional LSDA NC NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
BLYP NC NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
B1B95 NC NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
B3LYP NC NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
B3LYPultrafine   NC
NC
    NC
NC
NC
NC
NC
NC
NC
NC
      NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
B3PW91 NC NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
mPW1PW91 NC NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
M06-2X NC NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
PBEPBE NC NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
PBEPBEultrafine   NC
NC
    NC
NC
NC
NC
NC
NC
NC
NC
      NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
PBE1PBE NC NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
HSEh1PBE NC NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
TPSSh NC NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
wB97X-D NC NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
B97D3 NC NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC NC NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
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 daug-cc-pVTZ
Moller Plesset perturbation MP2 NC NC NC NC NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
MP2=FULL NC NC
NC
NC
NC
NC NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
MP3         NC
NC
  NC
NC
        NC
NC
NC
NC
NC
NC
     
MP3=FULL   NC
NC
NC
NC
NC NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
MP4   NC     NC
NC
      NC     NC
NC
NC
NC
NC
NC
NC
NC

NC
 
MP4=FULL   NC     NC
NC
      NC       NC
NC
NC
NC
NC
NC
NC
NC
 
B2PLYP NC NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
B2PLYP=FULL NC NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
Configuration interaction CID   NC
NC
NC
NC
NC
NC
NC
NC
    NC
NC
                 
CISD   NC
NC
NC
NC
NC
NC
NC
NC
    NC
NC
                 
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 daug-cc-pVTZ
Quadratic configuration interaction QCISD   NC
NC
NC
NC
NC NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC

NC
 
QCISD(T)         NC
NC
    NC
NC
      NC
NC
NC
NC
NC
NC
NC
NC
   
QCISD(T)=FULL         NC
NC
  NC
NC
          NC
NC
NC
NC
NC
NC
   
Coupled Cluster CCD   NC NC NC NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
CCSD         NC
NC
        NC   NC
NC
NC
NC
NC
NC
NC
NC

NC
 
CCSD=FULL         NC
NC
        NC   NC
NC
NC
NC
NC
NC
NC
NC
   
CCSD(T)         NC
NC
NC
NC
NC
NC
NC
NC
NC NC   NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
 
CCSD(T)=FULL         NC
NC
            NC
NC
NC
NC
NC
NC
NC
NC
   
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 daug-cc-pVTZ

Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD cc-pVTZ-PP aug-cc-pVTZ-PP Def2TZVPP
hartree fock HF -85304.9 a
-84963.7 b
-85535.9 a -85329.9 a
-85018.5 b
-85575.6 a NC
NC
NC
NC
    NC
NC
density functional B3LYP -87597.6 a
-87287.3 b
-87747.3 a -87625.7 a
-87335.8 b
-87789.2 a NC
NC
NC
NC
    NC
NC
PBEPBE                 NC
NC
wB97X-D -87613.6 a
-87297.7 b
-87767.9 a -87642.1 a
-87349.5 b
-87810.1 a NC
NC
NC
NC
     
Moller Plesset perturbation MP2 -86274.9 a -86979.4 a -86403.1 a -87107.3 a NC
NC
NC
NC
    NC
NC
NC = not calculated
For descriptions of the methods (AM1, HF, MP2, ...) and basis sets (3-21G, 3-21G*, 6-31G, ...) see the glossary in section I.C. Predefined means the basis set used is determined by the method.
gaw refers to the group additivity method implemeted in the NIST Chemistry Webbook.
See section Calculated; Vibrations; Scale Factors; Scale factors to list vibrational scaling factors.
See section Calculated; Vibrations; Scale Factors; Calculate a scale factor to calculate a vibrational scaling factor for a given set of molecules.