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/aug-cc-pVTZ

formula	sketch		Energy (kJ mol-1)		Name		difference
	A	B	calculated	experiment	A	B
C3H4			-18	-7	allene	propyne	-11
C4H6			-38	-51	1,2-Butadiene	1,3-Butadiene	13
C4H6			-9	3	1,2-Butadiene	1-Butyne	-12
C4H6			-31	-49	Cyclobutene	1,3-Butadiene	18
C4H6			-67	-82	1-Methylcyclopropene	1,2-Butadiene	15
C4H6			42	42	Methylenecyclopropane	1-Methylcyclopropene	-0
C3H6O			-111	-110	Oxetane	Propanal	-1
C4H8			-22	-33	cyclobutane	1-Butene	11
C5H8			-51	-52	1,2-Butadiene, 3-methyl-	1,3-Butadiene, 2-methyl-	0