Assertion: borax's boron | /r/MadeOf | bbr 3
Facets:
value: with hydrogen
type: OTHER
value: on an electrically heated tantalum filament
type: LOCATION
Source sentences:
text: Crystalline boron can be made with difficulty by “reduction of its bromide or chloride (BBr 3 , BCl 3 ) with hydrogen on an electrically heated tantalum filament.