Assertion: phosphorus's form | /r/HasProperty | allotropic
Facets:
Source sentences:
text: Phosphorus exists in at least 3 allotropic forms.
text: Phosphorus exists in four or more allotropic forms: white (or yellow), red, and black (or violet).
text: Phosphorus exists in three allotropic forms: white, black, and red.
text: Phosphorus exists in at least three allotropic forms.
text: It was discovered in 1669 by Hennig Brand and has two allotropic forms and eighteen isotopes.