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

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

Isomers of C5H6

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a C5H6 542927 1,3-Cyclopentadiene 0.0 sketch of 1,3-Cyclopentadiene
b C5H6 1574409 3-Penten-1-yne, (Z)- 123.9 sketch of 3-Penten-1-yne, (Z)-
c C5H6 78808 1-Buten-3-yne, 2-methyl- 124.3 sketch of 1-Buten-3-yne, 2-methyl-
d C5H6 2004695 3-Penten-1-yne, (E)- 124.7 sketch of 3-Penten-1-yne, (E)-
e C5H6 6746947 Cyclopropylacetylene 157.7 sketch of Cyclopropylacetylene
f C5H6 5164352 Bicyclo[2.1.0]pent-2-ene 198.7 sketch of Bicyclo[2.1.0]pent-2-ene
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
semi-empirical AM1 0.0 a
-149.9 b
-139.3 c
-152.5 d
-89.7 e
17.7 f
PM3 0.0 a
-137.0 b
-133.3 c
-139.8 d
-80.4 e
-7.0 f
PM6 0.0 a
105.8 b
104.4 c
103.1 d
143.4 e
176.1 f
MNDOd 0.0 a
99.3 b
109.1 c
97.4 d
139.4 e
191.5 f
composite G1 0.0 a
147.1 e
-67.9 f
G2MP2 0.0 a
145.4 e
-73.9 f
G2 0.0 a
146.3 e
-73.4 f
G3 0.0 a
91.7 b
89.6 c
90.9 d
146.9 e
-264.4 f
G3B3 0.0 a
-136.0 b
-136.7 c
-135.2 d
-88.8 e
-50.5 f
G3MP2 0.0 a
93.1 b
91.5 c
92.9 d
150.5 e
-66.8 f
G4 0.0 a
-132.9 b
-133.7 c
-132.2 d
-87.6 e
-51.8 f
CBS-Q 0.0 a
-173.1 b
-164.9 c
-167.2 d
-109.6 e
-260.5 f
Group additivity gaw
256.0 b
256.0 d
molecular mechanics MM3 0.0 a
286.1 b
286.8 c
284.3 d
189.4 e
405.2 f

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
hartree fock HF
  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f
 
  b
  c
  d
  e
  f
 
  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f
0.0 a
101.9 b
103.8 c
100.8 d
151.2 e
214.7 f
density functional LSDA 0.0 a
221.6 b
229.0 c
223.3 d
227.7 e
187.6 f
0.0 a
154.0 b
162.8 c
157.7 d
198.8 e
210.9 f
0.0 a
154.0 b
162.8 c
157.7 d
198.8 e
210.9 f
0.0 a
155.5 b
163.9 c
157.9 d
199.5 e
212.3 f
0.0 a
166.8 b
174.4 c
169.4 d
192.9 e
178.7 f
0.0 a
167.4 b
175.2 c
170.1 d
193.7 e
179.1 f
0.0 a
164.9 b
171.8 c
167.2 d
190.0 e
179.9 f
0.0 a
156.8 b
164.5 c
159.4 d
185.4 e
184.4 f
0.0 a
156.2 b
163.9 c
159.2 d
184.4 e
183.6 f
0.0 a
162.8 b
169.8 c
165.9 d
188.7 e
179.0 f
  0.0 a
170.9 b
178.9 c
173.6 d
198.2 e
181.3 f
0.0 a
157.4 b
164.7 c
160.2 d
185.0 e
184.8 f
0.0 a
170.4 b
176.4 c
172.9 d
194.4 e
181.6 f
  0.0 a
157.4 b
164.7 c
160.2 d
185.0 e
184.8 f
BLYP
  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f
 
  b
  c
  d
  e
  f

  e

  b
  c
  d
  e
  f
  0.0 a
153.8 e
B1B95
  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f
 
  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f
  0.0 a
130.0 b
134.8 c
130.7 d
160.4 e
180.3 f
B3LYP
  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f
0.0 a
122.6 c
119.1 d
168.0 e
203.0 f
  0.0 a
105.7 b
110.0 c
105.6 d
158.2 e
205.7 f
B3LYPultrafine        
  b
  c
  d
  e
  f
                     
B3PW91
  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f
 
  b
  c
  d
  e
  f
0.0 a
126.7 b
131.7 c
126.9 d
164.3 e
191.8 f

  b
  c
  d
  e
  f
  0.0 a
126.7 b
131.7 c
126.9 d
164.3 e
191.8 f
mPW1PW91
  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f
 
  b
  c
  d
  e
  f
0.0 a
132.3 b
137.1 c
132.7 d
166.6 e
190.3 f

  b
  c
  d
  e
  f
  0.0 a
132.3 b
137.1 c
132.7 d
166.6 e
190.3 f
PBEPBE
  b
  c
  d
  e
  f

  b
  c
  d
  e
  f
0.0 a
127.3 b
133.7 c
128.6 d
181.6 e
209.2 f
0.0 a
123.3 b
129.9 c
123.8 d
179.0 e
213.7 f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f
0.0 a
136.2 b
140.9 c
136.6 d
172.9 e
184.3 f
  0.0 a
124.6 b
130.3 c
125.2 d
164.9 e
187.1 f
PBEPBEultrafine        
  b
  c
  d
  e
  f
                     
Moller Plesset perturbation MP2
  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f
 
  b
  c
  d
  e
  f
 
  c
  d
  e
  f

  b
  c
  d
  e
  f
0.0 a
120.1 b
120.5 c
122.2 d
151.2 e
183.9 f
 
  b
  c
  d
  e
  f
     
NC
NC
MP2=FULL  
  f
 
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  f

  b
  c
  d
  f

  b
  c
  d
  e
  f
   
  f
       
MP3        
  b
  c
  d
  e
  f
                     
Configuration interaction CID        
NC
NC
NC
NC
                     
CISD        
NC
NC
NC
                     
Quadratic configuration interaction QCISD  
  b
  c
  d
  e
  f

  e
  f

  e
  f

  e
  f

  e
  f

  f

  e
  f
0.0 a    
  e
  f
       
Coupled Cluster CCD  
  e
  f

  e
  f

  e
  f

  b
  c
  d
  e
  f

  e
  f

  e
  f

  e
  f
     
  e
  f
       

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

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f
density functional B1B95
  b
  c
  d
  e
  f
0.0 a
174.5 b
176.7 c
172.8 d
188.1 e
156.6 f
       
B3LYP 0.0 a
140.8 b
143.2 c
138.8 d
195.5 e
214.1 f
0.0 a
150.4 b
151.6 c
148.1 d
189.9 e
185.4 f
0.0 a
115.8 b
119.2 c
116.0 d
177.7 e
223.6 f
0.0 a
118.3 b
120.8 c
118.3 d
168.1 e
198.5 f
0.0 a
114.2 b
116.1 c
114.3 d
177.9 e
228.3 f

  b
  c
  d
  e
  f
Moller Plesset perturbation MP2
  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

  b
  c
  d
  e
  f

Single point energy calculations (select basis sets)
6-311+G(3df,2p) cc-pVDZ cc-pVTZ aug-cc-pVDZ cc-pV(T+d)Z
Moller Plesset perturbation MP2FC// HF/6-31G*   0.0 a
115.8 b
114.4 c
115.0 d
157.8 e
-71.9 f
0.0 a
104.5 b
98.0 c
271.2 d
144.8 e
-66.4 f
  0.0 a
104.5 b
98.0 c
271.2 d
144.8 e
-66.4 f
MP2FC// B3LYP/6-31G*   0.0 a
-115.7 b
-115.3 c
-114.7 d
-79.9 e
-53.0 f
     
MP2FC// MP2FC/6-31G* 0.0 a
-60.8 f
0.0 a 0.0 a
-363.1 b
-91.6 e
-56.6 f

  b
  c
  d
  e
  f
0.0 a
-363.1 b
-91.6 e
-56.6 f
MP4// HF/6-31G*   0.0 a
112.2 b
110.9 c
110.7 d
160.9 e
-66.3 f
     
MP4// MP2/6-31G* 0.0 a
-55.4 f
       
Coupled Cluster CCSD// HF/6-31G*   0.0 a
112.0 b
111.0 c
110.3 d
161.7 e
-65.9 f

NC
 
NC
CCSD(T)// HF/6-31G*  
  b
  c
  d
  e
  f

NC
 
NC
CCSD(T)//B3LYP/6-31G(2df,p)     0.0 a
-123.1 b
-122.5 c
-121.9 d
  0.0 a
-123.1 b
-122.5 c
-121.9 d
CCSD// MP2FC/6-31G* 0.0 a
-54.9 f
0.0 a 0.0 a
-365.2 b
  0.0 a
-365.2 b
CCSD(T)// MP2FC/6-31G*
  f
0.0 a 0.0 a   0.0 a
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.