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: B1B95/3-21G

formula	sketch		Energy (kJ mol-1)		Name		difference
	A	B	calculated	experiment	A	B
C3H4			-1	-7	allene	propyne	6
C4H6			-36	-51	1,2-Butadiene	1,3-Butadiene	15
C4H6			16	3	1,2-Butadiene	1-Butyne	13
C4H6			-14	-17	1,2-Butadiene	2-Butyne	3
C4H6			-44	-49	Cyclobutene	1,3-Butadiene	5
C4H6			-108	-82	1-Methylcyclopropene	1,2-Butadiene	-26
C4H6			65	42	Methylenecyclopropane	1-Methylcyclopropene	24
C3H6O			-98	-110	Oxetane	Propanal	12
C4H8			-8	-33	cyclobutane	1-Butene	25
C3H4O2			15	29	2-Propenoic acid	β–Propiolactone	-14
C5H8			-37	-52	1,2-Butadiene, 3-methyl-	1,3-Butadiene, 2-methyl-	15
C5H8			31	25	1,3-Pentadiene, (E)-	1,4-Pentadiene	6
C5H8			49	64	1,3-Pentadiene, (E)-	1,2-Pentadiene	-15
C5H10			-31	-29	Cyclopropane, 1,1-dimethyl-	1-Butene, 2-methyl-	-2
C5H10			-8	-5	1-Butene, 2-methyl-	2-Butene, 2-methyl-	-3