Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
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Relative enthalpies of isomers - Comparison of 0K enthalpies (kJ mol^-1)

Isomers of C₄H₈

index	Species	CAS number	Name	Relative experimental enthalpy (kJ mol-1)	sketch
a	CH2CHCH2CH3	106989	1-Butene	16.4
b	CH2C(CH3)CH3	115117	1-Propene, 2-methyl-	0.0
c	C4H8	287230	cyclobutane	49.0
d	CH3CHCHCH3	590181	2-Butene, (Z)-
e	C4H8	594116	methylcyclopropane
f	CH3CHCHCH3	624646	2-Butene, (E)-