Assertion: nitrogen dioxide's gas | /r/HasProperty | helium
Facets:
Source sentences:
text: (6) William Ramsay discovered or codiscovered most of the other noble gases: helium, neon, krypton and xenon.
text: The principal gases provided are nitrogen, oxygen, carbon dioxide, argon, hydrogen, helium and acetylene, although many other gases and mixtures are also available in gas cylinders.
text: industrial gases”  is sometimes narrowly defined as just the major gases sold, which are: nitrogen, oxygen, carbon dioxide, argon, hydrogen, acetylene and helium.