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IV.A.4. (XIV.F.)

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

Isomers of CH2N2

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a HNCNH 151519 diiminomethane   sketch of diiminomethane
b CH2NN 157222 diazirine   sketch of diazirine
c NH2CN 420042 cyanamide 0.0 sketch of cyanamide
d CH2NN 334883 diazomethane 72.0 sketch of diazomethane
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
semi-empirical AM1
0.0 c
132.4 d
PM3
0.0 c
96.9 d
PM6 -60.3 a
253.8 b
0.0 c
91.2 d
composite G1 -277.1 a
-201.1 b
0.0 c
-71.2 d
G2MP2 -280.7 a
-206.7 b
0.0 c
-73.9 d
G2 -279.7 a
-205.5 b
0.0 c
-71.7 d
G3 -279.2 a
-196.5 b
0.0 c
-71.3 d
G3B3 -77.9 a
93.6 b
0.0 c
42.2 d
G3MP2 -276.8 a
-195.9 b
0.0 c
-69.5 d
G4 7.2 a
170.8 b
0.0 c
122.8 d
CBS-Q 2.1 a
176.3 b
0.0 c
118.8 d

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) cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z cc-pCVDZ cc-pCVTZ
hartree fock HF
  d

  d

  d

  d
 
  d
 
  d

  d

  d

  d

  d

  d

  d
 
NC

NC

NC
density functional LSDA
NC

  d

  d

  d

  d

  d

  d

  d

NC

NC
 
  d

  d

  d
 
NC
   
BLYP
  d

  d

  d

  d

  d

  d

  d

  d

  d

  d
   
  d
   
NC
   
B1B95
  d

  d

  d

  d

  d

  d

  d

  d

  d

  d

NC

  d

  d

  d

NC

NC
   
B3LYP    
  d

  d

  d

  d

  d

  d

  d
   
  d

  d

  d
 
NC
   
B3LYPultrafine        
  d
                         
B3PW91
  d

  d

  d

  d

  d

  d

  d

  d

  d

  d
 
  d

  d
   
NC
   
mPW1PW91
  d

  d

  d

  d

  d

  d

  d

  d

  d

  d
 
  d

  d
   
NC
   
PBEPBE
  d

  d

  d

  d

  d

  d

  d

  d

  d

  d
 
  d

  d
   
NC
   
Moller Plesset perturbation MP2
  d

  d

  d

  d
 
  d
 
  d

  d

  d
 
  d
 
  d

  d

NC

NC

NC
MP2=FULL
  d

  d

  d

  d
 
  d

  d

  d

  d

  d
 
  d
     
NC

NC

NC
MP3        
  d
                         
MP4
  d

  d
   
  d
     
  d

  d
               
Configuration interaction CID  
  d
   
  d
       
  d
               
CISD  
  d
   
  d
       
  d
               
Quadratic configuration interaction QCISD
  d

  d
 
  d

  d

  d

  d

  d

  d

  d
 
  d

  d
   
NC
   
QCISD(T)        
  d
     
  d
                 
Coupled Cluster CCD
  d

  d
 
  d

  d

  d

  d

  d

  d

  d
 
  d

  d
   
NC
   
CCSD        
NC
     
NC
                 
CCSD(T)        
  d
     
  d
   
NC
 
NC

NC
 
NC

NC
CCSD(T)=FULL        
NC
           
NC
       
NC

NC

Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF
  d

  d

  d

  d

  d

  d
density functional B1B95
  d

-69604.1 d
       
B3LYP
  d

  d

  d

  d

  d

  d
Moller Plesset perturbation MP2
  d

  d

  d

  d

  d

  d
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 III.C.1 List or set vibrational scaling factors to change the scale factors used here.
See section III.C.2 Calculate a vibrational scaling factor for a given set of molecules to determine the least squares best scaling factor.