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

Isomers of CHNO

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a HOCN 420053 cyanic acid   sketch of cyanic acid
b HCNO 506854 fulminic acid   sketch of fulminic acid
c HNCO 75138 Isocyanic acid 0.0 sketch of Isocyanic acid
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
semi-empirical AM1
341.6 b
0.0 c
PM3 64.7 a
189.6 b
0.0 c
PM6
157.6 b
MNDOd
0.0 c
composite G1 105.8 a
348.4 b
0.0 c
G2MP2 109.7 a
348.2 b
0.0 c
G2 108.5 a
349.3 b
0.0 c
G3 107.5 a
344.7 b
0.0 c
G3B3 103.4 a
333.2 b
0.0 c
G3MP2 107.1 a
348.4 b
0.0 c
G4 103.8 a
331.5 b
0.0 c
CBS-Q 107.9 a
351.8 b
0.0 c
molecular mechanics MM3
0.0 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 cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z daug-cc-pVTZ
hartree fock HF -19.8 a
345.2 b
0.0 c
84.2 a
402.8 b
0.0 c
84.2 a
402.8 b
0.0 c
85.8 a
379.2 b
0.0 c
105.8 a
401.2 b
0.0 c
99.6 a
407.1 b
0.0 c
98.8 a
403.5 b
0.0 c
110.5 a
408.9 b
0.0 c
101.8 a
412.3 b
0.0 c
104.8 a
408.1 b
0.0 c
105.7 a
0.0 c
98.7 a
407.7 b
0.0 c
102.2 a
408.0 b
0.0 c
103.5 a
406.8 b
0.0 c
104.2 a
0.0 c
103.0 a
407.5 b
0.0 c
103.8 a
405.8 b
0.0 c
103.5 a
350.2 b
0.0 c
103.8 a
405.8 b
0.0 c
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
NC
NC
 
BLYP 69.4 a
265.2 b
0.0 c
120.7 a
312.3 b
0.0 c
120.7 a
312.3 b
0.0 c
122.9 a
292.4 b
0.0 c
126.7 a
300.0 b
0.0 c
122.1 a
304.7 b
0.0 c
120.1 a
306.2 b
0.0 c
131.9 a
308.6 b
0.0 c
124.5 a
312.1 b
0.0 c
124.1 a
306.4 b
0.0 c
 
NC

299.7 b
0.0 c

310.6 b
0.0 c
 
0.0 c
 
0.0 c
 
B1B95 54.0 a
305.2 b
0.0 c
116.0 a
357.2 b
0.0 c
116.0 a
357.2 b
0.0 c
116.8 a
335.6 b
0.0 c
112.1 a
331.2 b
0.0 c
117.9 a
352.4 b
0.0 c
116.3 a
346.8 b
0.0 c
128.6 a
350.9 b
0.0 c
120.4 a
354.3 b
0.0 c

347.2 b
0.0 c
 
NC
118.6 a
344.2 b
0.0 c
108.3 a
340.1 b
0.0 c
 
338.3 b
0.0 c

NC
108.3 a
272.9 b
0.0 c
 
B3LYP 53.5 a
290.0 b
0.0 c
115.1 a
338.9 b
0.0 c
115.1 a
338.9 b
0.0 c
116.8 a
315.3 b
0.0 c
122.7 a
327.0 b
0.0 c
117.9 a
331.8 b
0.0 c
116.3 a
331.6 b
0.0 c
128.2 a
336.7 b
0.0 c
120.3 a
338.4 b
0.0 c
120.5 a
334.0 b
0.0 c

0.0 c
119.1 a
335.0 b
0.0 c
117.8 a
327.3 b
0.0 c
119.8 a
335.9 b
0.0 c
  117.3 a
334.0 b
0.0 c
119.7 a
335.7 b
0.0 c
119.8 a
285.6 b
0.0 c
 
B3LYPultrafine  
NC
    122.7 a
327.0 b
0.0 c

NC
116.3 a
331.7 b
0.0 c

NC
     
NC

NC
119.8 a
337.5 b
0.0 c
 
NC
119.7 a
335.7 b
0.0 c
   
B3PW91 58.6 a
291.4 b
0.0 c
119.2 a
340.6 b
0.0 c
119.2 a
340.6 b
0.0 c
119.8 a
317.6 b
0.0 c
125.9 a
326.1 b
0.0 c
120.8 a
332.6 b
0.0 c
119.2 a
330.4 b
0.0 c
131.9 a
334.3 b
0.0 c
123.7 a
337.6 b
0.0 c
123.1 a
331.8 b
0.0 c
 
NC
121.7 a
327.5 b
0.0 c
122.7 a
333.8 b
0.0 c
 
0.0 c
  122.7 a
283.2 b
0.0 c
 
mPW1PW91 54.3 a
297.4 b
0.0 c
114.2 a
343.2 b
0.0 c
117.5 a
346.4 b
0.0 c
118.0 a
322.6 b
0.0 c
122.0 a
328.3 b
0.0 c
116.8 a
332.9 b
0.0 c
115.4 a
332.2 b
0.0 c
128.1 a
336.7 b
0.0 c
122.6 a
343.0 b
0.0 c
122.2 a
337.2 b
0.0 c
 
NC
117.9 a
330.6 b
0.0 c
118.9 a
335.9 b
0.0 c
 
337.9 b
0.0 c

NC
118.9 a
284.4 b
0.0 c
 
M06-2X
NC

NC
96.9 a
358.1 b
0.0 c

NC
106.7 a
340.7 b
0.0 c

NC

NC

NC

NC

NC
 
NC

NC

NC
 
NC

NC
   
PBEPBE 77.0 a
268.2 b
0.0 c
126.0 a
316.4 b
0.0 c
126.0 a
316.4 b
0.0 c
127.5 a
296.1 b
0.0 c
131.2 a
297.6 b
0.0 c
126.4 a
302.6 b
0.0 c
124.3 a
303.6 b
0.0 c
136.9 a
306.0 b
0.0 c
128.9 a
309.9 b
0.0 c
127.9 a
303.7 b
0.0 c
 
NC
126.8 a
298.6 b
0.0 c
127.2 a
307.1 b
0.0 c
 
305.2 b
0.0 c
127.0 a
307.5 b
0.0 c
127.2 a
261.3 b
0.0 c
 
PBEPBEultrafine  
NC
    131.2 a
297.6 b
0.0 c

NC

NC

NC
     
NC

NC

NC
 
NC

NC
   
PBE1PBE
NC

NC

NC

NC
125.5 a
329.4 b
0.0 c

NC

NC

NC

NC

NC
 
NC

NC

NC
 
NC

NC
   
HSEh1PBE
NC
118.8 a
344.9 b
0.0 c

NC

NC
125.7 a
329.0 b
0.0 c

NC
118.9 a
333.3 b
0.0 c

NC

NC

NC
 
NC

NC
122.3 a
336.6 b
0.0 c
 
NC

NC
   
TPSSh         126.5 a
314.3 b
0.0 c

NC
120.2 a
0.0 c

NC
  123.5 a
0.0 c
 
NC

NC
123.2 a
321.7 b
0.0 c
 
NC

NC
   
wB97X-D     116.6 a
0.0 c
  122.2 a
339.1 b
0.0 c
  115.4 a
0.0 c
  119.9 a
0.0 c
    117.8 a
0.0 c
115.4 a
0.0 c
119.2 a
346.6 b
0.0 c
    119.0 a
0.0 c
   
B97D3   123.1 a
322.0 b
0.0 c
    129.5 a
304.0 b
0.0 c
  122.9 a
309.5 b
0.0 c
  127.3 a
315.4 b
0.0 c
  127.8 a
315.4 b
0.0 c
125.6 a
312.4 b
0.0 c
  126.2 a
312.5 b
0.0 c
    126.0 a
313.0 b
0.0 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 cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z daug-cc-pVTZ
Moller Plesset perturbation MP2 -2.9 a
266.5 b
0.0 c
88.4 a
333.6 b
0.0 c
88.4 a
333.6 b
0.0 c
87.2 a
303.2 b
0.0 c
105.6 a
316.5 b
0.0 c
101.0 a
322.5 b
0.0 c

  b
113.1 a
321.3 b
0.0 c
101.4 a
327.9 b
0.0 c
106.7 a
323.8 b
0.0 c
  101.3 a
323.7 b
0.0 c
101.0 a
320.2 b
0.0 c
103.9 a
323.0 b
0.0 c
  103.3 a
323.4 b
0.0 c

NC
103.9 a
278.0 b
0.0 c
 
MP2=FULL NC
NC
88.4 a
331.6 b
0.0 c
88.4 a
331.6 b
0.0 c
87.2 a
303.1 b
0.0 c
106.2 a
317.3 b
0.0 c
101.7 a
323.3 b
0.0 c
100.7 a
320.6 b
0.0 c
113.4 a
321.4 b
0.0 c
101.9 a
327.9 b
0.0 c
NC
NC
 
NC
101.5 a
320.2 b
0.0 c
105.9 a
321.0 b
0.0 c
 
323.6 b
0.0 c

NC
105.9 a
275.6 b
0.0 c
 
MP3        
351.0 b
0.0 c
 
329.0 b
0.0 c
       
NC

NC

NC
         
MP3=FULL         96.1 a
351.6 b
0.0 c
  91.2 a
354.9 b
0.0 c
       
NC

NC

NC
         
MP4  
NC
   
310.3 b
0.0 c
     
NC
   
NC

NC
107.7 a
316.3 b
0.0 c
 
NC

NC
   
MP4=FULL  
NC
   
NC
     
NC
     
NC

NC
 
NC

NC
   
B2PLYP
NC

NC

NC

NC
  a
  b

NC

NC

NC

NC

NC
 
NC

NC
114.3 a
330.1 b
0.0 c
 
NC

NC
   
B2PLYP=FULL
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   81.8 a
354.3 b
0.0 c
NC
NC
NC
NC
103.1 a
360.8 b
0.0 c
    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 cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z daug-cc-pVTZ
Quadratic configuration interaction QCISD NC
NC
79.6 a
330.3 b
0.0 c
79.6 a
330.3 b
0.0 c
79.8 a
305.3 b
0.0 c
99.9 a
336.6 b
0.0 c
95.4 a
342.0 b
0.0 c
93.8 a
338.8 b
0.0 c
107.2 a
346.1 b
0.0 c
96.2 a
350.6 b
0.0 c
NC
NC
 
NC
96.5 a
341.8 b
0.0 c
98.9 a
350.2 b
0.0 c
 
NC

NC
98.9 a
298.5 b
0.0 c
 
QCISD(T)        
324.3 b
0.0 c
           
NC

NC

NC
 
NC

NC
   
QCISD(T)=FULL        
NC
 
NC
         
NC

NC
 
NC

NC
   
QCISD(TQ)        
NC
 
NC
         
NC

NC
 
NC
     
QCISD(TQ)=FULL        
NC
 
NC
         
NC
   
NC
     
Coupled Cluster CCD NC
NC
67.6 a
337.9 b
0.0 c
67.6 a
337.9 b
0.0 c
68.9 a
314.4 b
0.0 c
93.0 a
344.6 b
0.0 c
88.6 a
351.0 b
0.0 c
87.9 a
347.4 b
0.0 c
100.4 a
351.1 b
0.0 c
NC
NC
NC
NC
 
NC
89.5 a
348.8 b
0.0 c
93.8 a
354.2 b
0.0 c
 
NC

NC
93.8 a
0.0 c
 
CCSD        
341.6 b
0.0 c
       
NC
 
NC

NC

NC
 
NC

NC
   
CCSD=FULL        
NC
       
NC
 
NC

NC

NC
 
NC

NC
   
CCSD(T)        
325.3 b
0.0 c
           
NC

NC

NC
 
NC

NC

NC
 
CCSD(T)=FULL        
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 cc-pVQZ 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 78.7 a
355.0 b
0.0 c
104.4 a
399.2 b
0.0 c
75.9 a
354.4 b
0.0 c
100.8 a
400.3 b
0.0 c
83.5 a
368.2 b
0.0 c
83.8 a
368.6 b
0.0 c
    103.8 a
407.0 b
0.0 c
density functional B1B95 114.1 a
258.6 b
0.0 c
121.0 a
276.7 b
0.0 c
             
B3LYP 107.3 a
304.0 b
0.0 c
118.3 a
328.7 b
0.0 c
105.0 a
301.1 b
0.0 c
116.6 a
330.9 b
0.0 c
113.7 a
307.6 b
0.0 c
113.9 a
307.9 b
0.0 c
    120.3 a
335.3 b
0.0 c
PBEPBE                 127.7 a
307.7 b
0.0 c
Moller Plesset perturbation MP2 78.3 a
291.8 b
0.0 c
103.4 a
319.6 b
0.0 c
75.7 a
291.0 b
0.0 c
101.4 a
317.4 b
0.0 c
82.5 a
296.8 b
0.0 c
82.3 a
297.0 b
0.0 c
    104.8 a
324.7 b
0.0 c

Single point energy calculations (select basis sets)
6-311+G(3df,2p) cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ cc-pV(T+d)Z
Moller Plesset perturbation MP2FC// HF/6-31G* 113.3 a
347.9 b
0.0 c

0.0 c
108.9 a
347.9 b
0.0 c

0.0 c

0.0 c
108.9 a
347.9 b
0.0 c
MP2FC// B3LYP/6-31G* 109.0 a
334.7 b
0.0 c
103.3 a
336.3 b
0.0 c
104.6 a
334.7 b
0.0 c

0.0 c

0.0 c
104.6 a
334.7 b
0.0 c
MP2FC// MP2FC/6-31G*
0.0 c

0.0 c
103.3 a
323.5 b
0.0 c
102.4 a
324.5 b
0.0 c
  103.3 a
323.5 b
0.0 c
MP4// HF/6-31G* 114.7 a
0.0 c

0.0 c
22.7 a
0.0 c
    22.7 a
254.7 b
0.0 c
MP4// B3LYP/6-31G*   107.5 a
0.0 c
107.8 a
0.0 c
    107.8 a
330.2 b
0.0 c
MP4// MP2/6-31G*
0.0 c
  106.9 a
317.8 b
0.0 c
    106.9 a
317.8 b
0.0 c
Coupled Cluster CCSD// HF/6-31G*
0.0 c

0.0 c

0.0 c

0.0 c

0.0 c

0.0 c
CCSD(T)// HF/6-31G*
0.0 c

0.0 c

0.0 c

0.0 c

0.0 c

0.0 c
CCSD// B3LYP/6-31G* 99.4 a
352.4 b
0.0 c

0.0 c

0.0 c
   
0.0 c
CCSD(T)// B3LYP/6-31G* 104.1 a
0.0 c

0.0 c

0.0 c
   
0.0 c
CCSD(T)//B3LYP/6-31G(2df,p)     100.4 a
341.4 b
0.0 c
    100.4 a
341.4 b
0.0 c
CCSD// MP2FC/6-31G*
0.0 c

0.0 c

0.0 c
93.2 a
348.0 b
0.0 c
 
0.0 c
CCSD(T)// MP2FC/6-31G*
0.0 c

0.0 c

0.0 c
97.3 a
334.6 b
0.0 c
 
0.0 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.