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: wB97X-D/6-311G**

formula	sketch		Energy (kJ mol-1)		Name		difference
	A	B	calculated	experiment	A	B
C3H4			4	-7	allene	propyne	10
C4H6			-41	-51	1,2-Butadiene	1,3-Butadiene	10
C4H6			13	3	1,2-Butadiene	1-Butyne	10
C4H6			-11	-17	1,2-Butadiene	2-Butyne	6
C4H6			-41	-49	Cyclobutene	1,3-Butadiene	9
C4H6			-76	-82	1-Methylcyclopropene	1,2-Butadiene	6
C4H6			48	42	Methylenecyclopropane	1-Methylcyclopropene	6
C3H6O			-112	-110	Oxetane	Propanal	-2
C4H8			-17	-33	cyclobutane	1-Butene	16
C3H4O2			31	29	2-Propenoic acid	β–Propiolactone	2
C4H6S			1	4	Thiophene, 2,5-dihydro-	Thiophene, 2,3-dihydro-	-3
C5H8			29	25	1,3-Pentadiene, (E)-	1,4-Pentadiene	3
C5H8			55	64	1,3-Pentadiene, (E)-	1,2-Pentadiene	-10
C5H8			-42	-52	1,2-Butadiene, 3-methyl-	1,3-Butadiene, 2-methyl-	9
C5H10			-9	-5	1-Butene, 2-methyl-	2-Butene, 2-methyl-	-4
C5H10			-19	-29	Cyclopropane, 1,1-dimethyl-	1-Butene, 2-methyl-	10