return to home page Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
You are here: Comparisons > Energy > Similar molecules > Isomers OR FAQ Help > List > Similar molecules > Isomers

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

Isomers of C8H10

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a CH3C6H4CH3 108383 meta-xylene 0.0 sketch of meta-xylene
b CH3C6H4CH3 106423 paraxylene 0.7 sketch of paraxylene
c C6H5CH2CH3 100414 Ethylbenzene 12.6 sketch of Ethylbenzene
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
semi-empirical AM1
35.6 c
PM3 0.0 a
-0.3 b
19.5 c
composite G1
NC
G2MP2
NC
G2
NC
G3
NC
G3B3 0.0 a
426.7 c
G3MP2
NC
G4 0.0 a
18.0 c

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 cc-pV(T+d)Z daug-cc-pVTZ
hartree fock HF
NC

NC

NC

NC
0.0 a
9.1 c

NC

NC

NC

NC
 
NC
0.0 a
8.3 c

NC

NC

NC

NC

NC

NC
density functional BLYP
NC

NC

NC

NC

  b
  c

NC

NC

NC

NC
     
NC

NC

NC
 
NC
 
B1B95
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

  c
  0.0 a
11.2 c

NC
 
NC

NC
   
B3LYPultrafine        
NC
               
NC
 
NC
   
B3PW91
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
 
M06-2X     0.0 a
4.5 c
                             
PBEPBE
NC

NC

NC

NC

NC

NC

NC

NC

NC
     
NC

NC
   
NC
 
PBEPBEultrafine        
NC
                         
PBE1PBE        
  c
                         
HSEh1PBE  
  c
    0.0 a
13.8 c
  0.0 a
12.6 c
            0.0 a
13.2 c
       
TPSSh        
  c
 
  c
   
  c
     
  c
       
wB97X-D    
  c
 
  c
 
  b
  c
 
  c
   
  b
  c

  b
  c

  c
 
  c
   
B97D3   0.0 a
6.8 c
   
  c
 
  c
 
  c
 
  c

  c
 
  c
 
  c
   
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 cc-pV(T+d)Z daug-cc-pVTZ
Moller Plesset perturbation MP2
NC

NC

NC

NC

  c

NC

NC

  c

NC
   
  c

NC

NC

NC

NC

NC
 
MP2=FULL
NC

NC

NC

NC

NC

NC

NC

NC

NC
     
NC

NC
   
NC
 
MP3        
NC
                         
MP3=FULL        
  c
 
  c
                     
B2PLYP         0.0 a
12.7 c
               
NC
       
Configuration interaction CID        
NC
                         
CISD        
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 cc-pV(T+d)Z daug-cc-pVTZ
Quadratic configuration interaction QCISD  
NC
 
NC

NC
                         
Coupled Cluster CCD  
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 cc-pV(T+d)Z 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
NC

NC

NC

NC

NC

NC
    0.0 a
8.7 c
density functional B1B95
NC

NC
             
B3LYP
NC

NC

NC

NC

NC

NC
   
  c
PBEPBE                 0.0 a
0.3 b
13.9 c
Moller Plesset perturbation MP2
NC

NC

NC

NC

NC

NC
   
  b
  c
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.