Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
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Relative enthalpies of isomers - Comparison of 298.15K enthalpies (kJ mol^-1)

Isomers of C₄H₄

index	Species	CAS number	Name	Relative experimental enthalpy (kJ mol-1)	sketch
a	C4H4	157391	Tetrahedrane
b	C4H4	1120532	cyclobutadiene
c	H2CCCCH2	2873509	Butatriene
d	C2H3CCH	689974	1-Buten-3-yne	0.0