Assertion: amorphous boron | /r/HasProperty | brown powder
Facets:
Source sentences:
text: Several allotropes of boron exist: amorphous boron is a brown powder; crystalline boron is silvery to black, extremely hard (about 9.5 on the Mohs scale), and a poor electrical conductor at room temperature.
text: Amorphous boron is a brown powder and metallic (crystalline) boron is black and hard and a weak conductor at room temperature.
text: Amorphous boron is a brown powder.
text: Amorphous boron is a brown powder.
text: Amorphous boron is a brown powder and metallic (crystalline) boron is black and hard and a weak conductor at room temperature.
text: There are two allotropes of boron; amorphous boron is a brown powder, but metallic boron is black.
text: There are two allotropes of boron; amorphous boron is a brown powder, but metallic boron is black.
text: Several allotropes of boron exist: amorphous boron is a brown powder; crystalline boron is silvery to black, extremely hard (about 9.5 on the Mohs scale), and a poor electrical conductor at room temperature.
text: Amorphous boron is a brown powder, while crystalline boron is black, extremely hard (about 9.5 on the Mohs scale), and a poor conductor at room temperature.
text: Several allotropes of boron exist: amorphous boron is a brown powder; whereas crystalline boron is black, extremely hard (about 9.5 on Mohs' scale), and a poor conductor at room temperature.