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 0K enthalpies (kJ mol^-1)

Isomers of C₄H₄

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