- Atomic Radius (Å)
Boron is a metalloid chemical element with symbol B and atomic number 5. Produced entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, it is a low-abundance element in both the Solar system and the Earth's crust. Boron is concentrated on Earth by the water-solubility of its more common naturally occurring compounds, the borate minerals.
5
Atomic Number
10.81
Atomic Mass (u)
2573.15
Melting Point (K)
4200
Boiling Point (K)
2.08
Density (solid: g/cm³, gas: g/liter)
1.2
Atomic Radius (Å)
0.84
Covalent Radius (Å)
2.04
Electronegativity
8.3
First Ionization Energy (eV)
26.99
Electron Affinity
2
Number of Shells
3
Electron Valency
2, 3
Electron Shell Occupations
1.03
Specific Heat (J/g)