Assertion: acetylene | /r/HasProperty | fluorine
Facets:
Source sentences:
text: The timeline of attributed discovery for various gases are carbon dioxide (1754), hydrogen (1766), nitrogen (1772), nitrous oxide (1772)  , oxygen (1773)  , ammonia (1774), chlorine (1774), methane (1776), hydrogen sulfide (1777), carbon monoxide (1800), hydrogen chloride (1810), acetylene (1836), helium (1868)  fluorine (1886), argon (1894), krypton, neon and xenon (1898)  and radon (1899).