Assertion: grey tetravalent metallic element | /r/ObjectUse | used in filament
Facets:
value: for its ready emission of electrons
type: PURPOSE
Source sentences:
text: atomic number 72; hafnium; Hf (a grey tetravalent metallic element that resembles zirconium chemically and is found in zirconium minerals; used in filaments for its ready emission of electrons)
text: Hf, atomic number 72, hafnium a grey tetravalent metallic element that resembles zirconium chemically and is found in zirconium minerals; used in filaments for its ready emission of electrons
text: Hf, atomic number 72, hafnium a grey tetravalent metallic element that resembles zirconium chemically and is found in zirconium minerals; used in filaments for its ready emission of electrons
text: hafnium a grey tetravalent metallic element that resembles zirconium chemically and is found in zirconium minerals; used in filaments for its ready emission of electrons