Assertion: vinylidene chloride | /r/HasProperty | needed
Facets:
Source sentences:
text: Vinylidene chloride is produced by the reaction of 1,1,2-trichloroethane (itself derived from acetylene or ethylene) with lime or with caustic soda; it usually is prepared only as it is needed because it is rapidly attacked by oxygen to form peroxides that catalyze the formation of undesired polymers.