Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
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Tautomer energy comparison

using model chemistry: LSDA/STO-3G

formula	sketch		Energy (kJ mol-1)		Name		difference
	A	B	calculated	experiment	A	B
C4H6			-40	-82	1-Methylcyclopropene	1,2-Butadiene	42
C4H6			53	42	Methylenecyclopropane	1-Methylcyclopropene	12
C4H6S			-24	4	Thiophene, 2,5-dihydro-	Thiophene, 2,3-dihydro-	-29
C5H8			45	25	1,3-Pentadiene, (E)-	1,4-Pentadiene	20
C5H8			60	64	1,3-Pentadiene, (E)-	1,2-Pentadiene	-4
C5H10			-17	-5	1-Butene, 2-methyl-	2-Butene, 2-methyl-	-12
C5H10			21	-29	Cyclopropane, 1,1-dimethyl-	1-Butene, 2-methyl-	50