Boron |
Symbol | B |
---|---|
Latin name | Borum |
Atomic number | 5 |
Period | 2 |
Element category | Metalloids |
Relative atomic mass | 10.811 |
Group | III.A |
Electronegativity | 2.0 |
Oxidation numbers | 3 |
Electron configuration | 1s2 2s2 2p1 |
Density [g/cm3] | 2.34 |
State | Solid |
Melting point [°C] | 2300 |
Boiling point [°C] | 2550 |
Atomic radius [pm] | 87 |
Covalent radius [pm] | 82 |
Thermal conductivity [W m-1K-1] | 27 |
Heat capacity [J K-1g-1] | 1.026 |
Discovery | 1808 |
Hardness [Mohs scale] | 9.3 |
Vickers hardness [MPa] | 4.9 · 104 |
Electrical conductivity [S m-1] | 5 · 10-6 |
1.st ionization energy [eV] | 8.298 |
2.nd ionization energy [eV] | 25.154 |
3.rd ionization energy [eV] | 37.93 |
Stable isotopes | 2 |
Unstable isotopes | 4 |