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: MP2/Def2TZVPP

formula	sketch		Energy (kJ mol-1)		Name		difference
	A	B	calculated	experiment	A	B
C3H4			-18	-7	allene	propyne	-11
C4H6			-43	-49	Cyclobutene	1,3-Butadiene	6
C4H6			-50	-51	1,2-Butadiene	1,3-Butadiene	1
C4H6			-9	3	1,2-Butadiene	1-Butyne	-12
C4H6			-30	-17	1,2-Butadiene	2-Butyne	-13
C4H6			-66	-82	1-Methylcyclopropene	1,2-Butadiene	16
C4H6			42	42	Methylenecyclopropane	1-Methylcyclopropene	0
C4H8			-21	-33	cyclobutane	1-Butene	12
C3H4O2			34	29	2-Propenoic acid	β–Propiolactone	6
C4H6S			-4	4	Thiophene, 2,5-dihydro-	Thiophene, 2,3-dihydro-	-9
C5H8			29	25	1,3-Pentadiene, (E)-	1,4-Pentadiene	4
C5H8			62	64	1,3-Pentadiene, (E)-	1,2-Pentadiene	-2
C5H8			-51	-52	1,2-Butadiene, 3-methyl-	1,3-Butadiene, 2-methyl-	0
C5H10			-8	-5	1-Butene, 2-methyl-	2-Butene, 2-methyl-	-2
C5H10			-15	-29	Cyclopropane, 1,1-dimethyl-	1-Butene, 2-methyl-	14