| Boron | |
| Electrons per shell | 2,3 |
| Electron Configuration | 1s2 2s2 2p1 ![]() |
| Ground state | 2P°1/2 |
| Atomic Volume | 4.6 cm3 mol-1 |
| Electronegativity | 2.04 |
| Magnetic ordering | Non-magnetic |
| Mass magnetic susceptibility | -8.7 x 10-9 |
| Molar magnetic susceptibility | -9.41 x 10-11 |
| Speed of sound | 16200 m s-1 |
Thermal Properties |
|
| Enthalpy of Atomization | 573.2 kJ mol-1 @25°C |
| Enthalpy of Fusion | 22.2 kJ mol-1 |
| Enthalpy of Vaporisation | 504.5 kJ mol-1 |
| Heat Capacity | 11.087 J mol-1 K-1 |
| Thermal Conductivity | 27.4 W m-1 K-1 |
| Thermal Expansion | 5 - 7 μm m-1 K-1 |
| Critcal Temperature | No data. |
| Critcal Pressure | No data. |
| Adiabatic index | No data. |
Hardness |
|
| Mohs hardness | 9.3 |
| Vickers hardness | 49000 MPa |
Elastic Properties |
|
| Bulk modulus | 185 GPa |
Electrical Properties |
|
| Electrical resistivity | 1.5 x 104 Ω m |
| Electrical conductivity | ? 106/cm Ω |
Chemical Properties |
|
| Electrochemical Equivalent | 0.1344 g Ah-1 |
| Electron Work Function | 4.45 eV |
| Valence Electron Potential (-eV) | 190 |
| Ionization Potential | |
| 8.298 | |
| 25.154 | |
| 37.93 | |
Energy Levels |
|
| 0.1833 KeV | |
Atomic Radii |
|
| 85 pm | |
| 87 pm | |
| 82 pm | |
| No data. | |
| 73 pm | |
| No data. | |
Ionic Radii (Å) |
||||
| Charge | Coordination | Crystal | Ionic | Key |
| 3 | III | 0.15 | 0.01 | * |
| IV | 0.25 | 0.11 | * | |
| VI | 0.41 | 0.27 | C | |
| R, From r3 vs V plots. |
| C, Calculated from bond length - bond strength equations. |
| E, Estimated. |
| *, Most Reliable. |
| M, From Metallic Oxides. |
| A, Ahrens (1952) Ionic radius. |
| P, Pauling's (1960) Crystal Radius. |
Oxidation States |
|
| B+3 | |
Ionisation Energies (kJ mol-1) ![]() |
|
| 800.6 | |
| 2427 | |
| 3660 | |
| 25025 | |
| 32822 | |
Covalent Bonds (kJ mol-1) |
|
| 381 | |
| 439 | |
| 372 | |
| 523 | |
| 644 | |
| 444 | |
| 335 | |
Vapour Pressure |
||||||
| P (Pa) | 1 | 10 | 100 | 1K | 10K | 100K |
| T (K) | 2348 | 2562 | 2822 | 3141 | 3545 | 4072 |
Crystal Structure |
|
| Rhombohedral | |
![]() |
a = 506 pm |
| b = 506 pm | |
| c = 506 pm | |
| α = 58.06° | |
| β = 58.06° | |
| γ = 58.06° | |