The major crystalline product derived from the ozonolysis of 1,2,3,4-t
etrachlorobut-2-ene has been shown to be the monocyclic ozonide title
compound, C4H4Cl4O3, (1), rather than the Z stereoisomer originally re
ported. The ozonide ring of (1) adopts a half-chair conformation. The
molecules pack together to form sheets linked together by a series of
Cl...Cl interactions.