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/LANL2DZ

formula	sketch		Energy (kJ mol-1)		Name		difference
	A	B	calculated	experiment	A	B
C3H4			-33	-7	allene	propyne	-26
C4H6			-76	-49	Cyclobutene	1,3-Butadiene	-27
C4H6			-52	-51	1,2-Butadiene	1,3-Butadiene	-1
C4H6			-24	3	1,2-Butadiene	1-Butyne	-27
C4H6			-108	-82	1-Methylcyclopropene	1,2-Butadiene	-26
C4H6			-41	-17	1,2-Butadiene	2-Butyne	-24
C4H6			51	42	Methylenecyclopropane	1-Methylcyclopropene	10
C3H6O			-133	-110	Oxetane	Propanal	-22
C4H8			-44	-33	cyclobutane	1-Butene	-11
C3H4O2			66	29	2-Propenoic acid	β–Propiolactone	37
C4H6S			9	4	Thiophene, 2,5-dihydro-	Thiophene, 2,3-dihydro-	5
C5H8			25	25	1,3-Pentadiene, (E)-	1,4-Pentadiene	0
C5H8			63	64	1,3-Pentadiene, (E)-	1,2-Pentadiene	-1
C5H8			-52	-52	1,2-Butadiene, 3-methyl-	1,3-Butadiene, 2-methyl-	-0
C5H10			-4	-5	1-Butene, 2-methyl-	2-Butene, 2-methyl-	1
C5H10			-48	-29	Cyclopropane, 1,1-dimethyl-	1-Butene, 2-methyl-	-19