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

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

Isomers of C6H12

index Species CAS number Name Relative experimental enthalpy (kJ mol-1) sketch
a C6H12 2398096 cis-1,3-dimethylcyclobutane   sketch of cis-1,3-dimethylcyclobutane
b C6H12 2398109 trans-1,3-dimethylcyclobutane   sketch of trans-1,3-dimethylcyclobutane
c C6H12 7688213 2-Hexene, (Z)-   sketch of 2-Hexene, (Z)-
d C6H12 13269528 e-Hex-3-ene   sketch of e-Hex-3-ene
e C6H12 15679013 cis-1,2-dimethylcyclobutane   sketch of cis-1,2-dimethylcyclobutane
f C6H12 15679024 trans-1,2-dimethylcyclobutane   sketch of trans-1,2-dimethylcyclobutane
g C4H6(CH3)2 18931710 dimethylcyclobutane   sketch of dimethylcyclobutane
h C6H12 110827 Cyclohexane 0.0 sketch of Cyclohexane
i C6H12 96377 Cyclopentane, methyl- 16.4 sketch of Cyclopentane, methyl-
j C6H12 563791 2-Butene, 2,3-dimethyl- 52.8 sketch of 2-Butene, 2,3-dimethyl-
k C6H12 563780 1-Butene, 2,3-dimethyl- 57.3 sketch of 1-Butene, 2,3-dimethyl-
l C6H12 616126 2-Pentene, 3-methyl-, (E)- 59.6 sketch of 2-Pentene, 3-methyl-, (E)-
m C6H12 922623 2-Pentene, 3-methyl-, (Z)- 61.3 sketch of 2-Pentene, 3-methyl-, (Z)-
n C6H12 760214 Pentane, 3-methylene- 67.1 sketch of Pentane, 3-methylene-
o C6H12 4050457 2-Hexene, (E)- 72.1 sketch of 2-Hexene, (E)-
p C6H12 592416 1-Hexene 81.0 sketch of 1-Hexene
q C6H12 4806615 Cyclobutane, ethyl- 95.4 sketch of Cyclobutane, ethyl-
The calculated enthalpies include the calculated and scaled vibrational zero-point energy.
Methods with predefined basis sets
semi-empirical AM1
67.7 c
92.7 g
0.0 h
-425.0 i
-350.6 j
-326.2 k
-347.7 l
-348.0 m
-334.7 n
-335.9 p
-338.6 q
PM3
36.9 g
0.0 h
-432.9 i
-401.6 j
-362.9 k
-386.4 l
-384.3 m
-366.1 n
-351.8 p
-373.1 q
PM6 -394.4 a
8.7 b
-377.0 c
-388.4 e
-393.9 f
2.6 g
0.0 h
-427.9 i
-414.9 j
-385.7 k
-396.0 l
-396.2 m
-379.0 n
417.1 o
-361.1 p
-381.4 q
MNDOd
0.0 h
8.0 i
90.6 j
115.4 k
83.5 l
99.3 n
111.1 p
57.3 q
composite G1
-917.5 b
-938.6 c
-925.3 g
0.0 h
-502.7 i
-500.2 j
-488.7 k
-488.8 m
-944.0 n
-463.6 p
G2MP2
-918.5 b
-937.0 c
-926.5 g
0.0 h
-502.6 i
-498.4 j
-487.4 k
-487.3 m
-942.4 n
-462.8 p
G2
-918.6 b
-937.2 c
-926.5 g
0.0 h
-502.7 i
-498.5 j
-487.5 k
-487.5 m
-942.8 n
-479.7 o
-462.9 p
G3
-916.6 b
-937.5 c
-924.5 g
0.0 h
-501.9 i
-499.2 j
-487.2 k
-487.6 l
-487.5 m
-942.2 n
-479.9 o
-463.2 p
-430.3 q
G3B3 -840.7 a
45.2 b
-413.6 c
-829.5 e
-841.5 f
-404.0 g
0.0 h
-463.0 i
-432.9 j
-427.5 k
-426.9 l
-427.0 m
-419.2 n
13.9 o
-408.1 p
-384.5 q
G3MP2
-924.0 g
0.0 h
-501.7 i
-500.5 j
-488.9 k
-489.4 l
-489.1 m
-943.5 n
-465.4 p
-430.3 q
G4
40.9 b
-410.7 c
-402.2 g
0.0 h
-459.9 i
-431.4 j
-425.1 k
-424.9 l
-424.7 m
-416.8 n
15.7 o
-404.8 p
-382.5 q
CBS-Q
46.1 b
29.7 c
42.8 g
0.0 h
21.2 o
molecular mechanics MM3
0.0 h
55.2 j
65.6 k
63.0 l
62.6 m
80.9 p
99.9 q

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
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  p

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0.0 h
18.0 i
58.5 j
59.1 k
54.6 l
54.6 m
59.1 n
64.9 p
98.4 q

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0.0 h
-454.7 i
-414.2 j
-412.9 k
-417.9 l
-417.8 m
-413.0 n
-373.8 q
density functional LSDA
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0.0 h
-411.8 i
-359.9 j
-343.3 k
-347.8 l
-346.4 m
-334.3 n
-321.0 p
-327.6 q
BLYP
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  j

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  j

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0.0 h
14.9 i
39.5 j
49.2 k
41.7 l
42.1 m
50.8 n
58.9 p
88.2 q
 
0.0 h
-419.2 i
-406.2 j
-394.3 k
-404.3 l
-403.7 m
-393.7 n
-385.3 p
-346.8 q
B1B95
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0.0 h
-432.6 i
-392.1 j
-378.2 k
-384.7 l
-384.0 m
-374.8 n
-365.5 p
-356.7 q
B3LYP
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0.0 h
15.6 i
41.6 j
51.3 k
43.7 l
44.2 m
53.3 n
61.7 p
92.0 q

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0.0 h
-429.5 i
-403.5 j
-393.1 k
-401.5 l
-400.9 m
-391.4 n
-383.3 p
-352.8 q
B3LYPultrafine        
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B3PW91
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0.0 h
16.4 i
66.9 j
77.8 k
70.4 l
71.0 m
80.5 n
88.8 p
95.3 q
 
0.0 h
-430.5 i
-389.0 j
-385.4 l
-384.8 m
-373.9 n
-365.7 p
-352.3 q
mPW1PW91
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0.0 h
17.1 i
72.6 j
82.7 k
76.4 l
76.9 m
85.9 n
94.6 p
97.3 q
 
0.0 h
-432.3 i
-385.7 j
-373.6 k
-381.7 l
-381.1 m
-370.6 n
-362.1 p
-352.7 q
PBEPBE
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0.0 h
14.8 i
50.2 j
63.6 k
55.4 l
56.0 m
67.4 n
77.1 p
89.9 q

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0.0 h
15.9 i
60.2 j
72.6 k
65.4 l
66.0 m
76.2 n
85.6 p
91.9 q
 
0.0 h
-418.6 i
-383.2 j
-368.9 k
-378.0 l
-377.3 m
-365.4 n
-356.2 p
-342.9 q
PBEPBEultrafine        
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Moller Plesset perturbation MP2
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  n
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MP2=FULL        
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MP3        
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Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF
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density functional B1B95
0.0 h
10.6 i
72.9 j
82.5 k
76.6 l
76.3 m
86.3 n
96.7 p
85.0 q

0.0 h
12.1 i
85.4 j
93.4 k
88.7 l
88.0 m
97.5 n
108.0 p
84.7 q
       
B3LYP
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Moller Plesset perturbation MP2
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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 h
-2698.4 i
-2677.7 j
-2590.8 k
-2600.6 l
-2585.5 m
-3056.2 n
-2552.4 p
-2577.3 q

0.0 h
-3197.3 i
-3184.5 j
-3114.6 k
-3111.4 l
-3105.5 m
-3578.6 n
-3078.1 p
-3081.2 q
 
0.0 h
-3197.3 i
-3184.5 j
-3114.6 k
-3111.4 l
-3105.5 m
-3578.6 n
-3078.1 p
-3081.2 q
MP2FC// B3LYP/6-31G*  
0.0 h
-430.9 i
-373.8 j
-370.0 k
-369.9 l
-370.0 m
-363.5 n
-350.7 p
-346.1 q
     
MP2FC// MP2FC/6-31G*
NC

0.0 h
-826.8 j
-361.7 p
 
0.0 h
-443.3 i
-831.0 j
-389.2 k
-828.2 l
-385.9 m
-381.8 n
-365.7 p
-359.2 q
 
MP4// MP2/6-31G*
NC
       
Coupled Cluster CCSD// MP2FC/6-31G*
NC
       
CCSD(T)// MP2FC/6-31G*
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 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.