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: B2PLYP/aug-cc-pVTZ

formula	sketch		Energy (kJ mol-1)		Name		difference
	A	B	calculated	experiment	A	B
C3H4			-2	-7	allene	propyne	5
C4H6			8	3	1,2-Butadiene	1-Butyne	5
C4H6			-84	-82	1-Methylcyclopropene	1,2-Butadiene	-2
C4H6			46	42	Methylenecyclopropane	1-Methylcyclopropene	5
C3H6O			-117	-110	Oxetane	Propanal	-6
C4H8			-36	-33	cyclobutane	1-Butene	-3