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/aug-cc-pVTZ

formula	sketch		Energy (kJ mol-1)		Name		difference
	A	B	calculated	experiment	A	B
C3H4			7	-7	allene	propyne	14
C4H6			-26	-51	1,2-Butadiene	1,3-Butadiene	25
C4H6			-26	-49	Cyclobutene	1,3-Butadiene	24
C4H6			-68	-82	1-Methylcyclopropene	1,2-Butadiene	14
C4H6			47	42	Methylenecyclopropane	1-Methylcyclopropene	5
C3H6O			-100	-110	Oxetane	Propanal	10
C4H8			-18	-33	cyclobutane	1-Butene	15
C5H8			-42	-52	1,2-Butadiene, 3-methyl-	1,3-Butadiene, 2-methyl-	10