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: TPSSh/6-31+G**

formula	sketch		Energy (kJ mol-1)		Name		difference
	A	B	calculated	experiment	A	B
C3H4			14	-7	allene	propyne	21
C4H6			-44	-51	1,2-Butadiene	1,3-Butadiene	8
C4H6			-44	-49	Cyclobutene	1,3-Butadiene	6
C4H6			25	3	1,2-Butadiene	1-Butyne	22
C4H6			-71	-82	1-Methylcyclopropene	1,2-Butadiene	11
C4H6			48	42	Methylenecyclopropane	1-Methylcyclopropene	6
C3H6O			-98	-110	Oxetane	Propanal	12
C4H8			-18	-33	cyclobutane	1-Butene	14
C3H4O2			19	29	2-Propenoic acid	β–Propiolactone	-9
C4H6S			-2	4	Thiophene, 2,5-dihydro-	Thiophene, 2,3-dihydro-	-6
C5H8			36	25	1,3-Pentadiene, (E)-	1,4-Pentadiene	10
C5H8			60	64	1,3-Pentadiene, (E)-	1,2-Pentadiene	-4
C5H8			-43	-52	1,2-Butadiene, 3-methyl-	1,3-Butadiene, 2-methyl-	9
C5H10			-11	-5	1-Butene, 2-methyl-	2-Butene, 2-methyl-	-5
C5H10			-17	-29	Cyclopropane, 1,1-dimethyl-	1-Butene, 2-methyl-	12