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: HF/STO-3G

formula	sketch		Energy (kJ mol-1)		Name		difference
	A	B	calculated	experiment	A	B
C3H4			-67	-7	allene	propyne	-60
C4H6			-35	-51	1,2-Butadiene	1,3-Butadiene	16
C4H6			-53	3	1,2-Butadiene	1-Butyne	-56
C4H6			-86	-17	1,2-Butadiene	2-Butyne	-69
C4H6			43	-49	Cyclobutene	1,3-Butadiene	92
C4H6			-42	-82	1-Methylcyclopropene	1,2-Butadiene	40
C4H6			48	42	Methylenecyclopropane	1-Methylcyclopropene	6
C3H6O			11	-110	Oxetane	Propanal	121
C4H8			79	-33	cyclobutane	1-Butene	111
C3H4O2			-106	29	2-Propenoic acid	β–Propiolactone	-134
C4H6S			-7	4	Thiophene, 2,5-dihydro-	Thiophene, 2,3-dihydro-	-11
C5H8			26	25	1,3-Pentadiene, (E)-	1,4-Pentadiene	1
C5H8			47	64	1,3-Pentadiene, (E)-	1,2-Pentadiene	-18
C5H10			-10	-5	1-Butene, 2-methyl-	2-Butene, 2-methyl-	-5
C5H10			15	-29	Cyclopropane, 1,1-dimethyl-	1-Butene, 2-methyl-	44