- A nonmetallic element whose atomic number is 5. It has various allotropic forms, the most common being as a brown amorphous powder, a black hard solid, or as extremely hard crystals. It has 10 known isotopes, of which 2 are stable. Boron has various applications, including its use as a neutron absorber, as a semiconductor dopant, and in various special alloys. Its chemical symbol is B.
- chemical symbolB