Assertion: impure boron | /r/HasProperty | obtained by french chemists
Facets:
value: by heating boric anhydride
type: MANNER
value: in 1808
type: TEMPORAL
Source sentences:
text: Free (impure) boron was first obtained by the French chemists J. Gay-Lussac and L. Thénard in 1808 by heating boric anhydride, B 2 O 3 , with metallic potassium.