Element: Boron
General data
| Element name | Boron |
|---|
| Chemical symbol | B |
|---|
| Atomic number Z | 5 |
|---|
| Year discovered | 1808 |
|---|
| Standard state (25°C) | Solid |
|---|
| Category | Metalloid |
|---|
| Block | p |
|---|
| Atomic mass | 10.81 |
|---|
| CPK color | #FFB5B5 |
|---|
Physical properties
| Melting point | 2348 K (2075 °C) |
|---|
| Boiling point | 4273 K (4000 °C) |
|---|
| Density | 2.37 g/cm³ |
|---|
Energy properties
| First ionization energy | 8.298 eV |
|---|
| Electron affinity | 0.277 eV |
|---|
Atomic structure
| Protons | 5 (Atomic number) |
|---|
| Neutrons (B-11, most abundant isotope) | 6 |
|---|
| Electrons | 5 |
|---|
| Electron configuration | [He] 2s² 2p¹ |
|---|
| Oxidation states | +3 |
|---|
| Electronegativity (Pauling) | 2.04 |
|---|
| Atomic radius (van der Waals) | 192 pm |
|---|
Ionization energies - NIST ASD (5 states)
Value type as given by NIST ASD: measured - from evaluated experimental data; calculated - from ab initio calculations (mostly highly ionised atoms that have not been measured; for the simplest ones, e.g. H I, the calculation is more accurate than measurement); semi-empirical - from interpolation, extrapolation or another semi-empirical method.
