Assertion: fluorine | /r/HasProperty | replaced with fluorine
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Source sentences:
text: The compound, however, lacks an ability to transform upon melting, which is not a problem for various PTFE deratives, namely FEP (fluorinated ethylene propylene, with some fluorines replaced with the–CF 3 group) or PFA (perfluoroalkoxy, some fluorines replaced with –OCF 3 ).