Assertion: fluorine's use | /r/HasProperty | introduced as refrigerant
Facets:
value: in the late 1920s
type: TEMPORAL
Source sentences:
text: The two most prominent uses of organofluorine compounds, Teflon (invented 1938), and hydrofluorocarbons and chlorofluorocarbons (for example Freon-12, introduced as a refrigerant in the late 1920s), are still major applications for fluorine.