Assertion: black phosphorus | /r/HasProperty | formed
Facets:
value: by heating white phosphorus
type: MANNER
Source sentences:
text: Black phosphorus is also formed by heating white phosphorus, but a mercury catalyst and a seed crystal of black phosphorus are required.
text: Black phosphorus is formed by heating white phosphorus to 200°–220
text: Black phosphorus is formed by heating white phosphorus to 200°–220