| Overview |
| Name | Boron |
| Symbol | B |
| Atomic Number | 5 |
| Atomic Weight | 10.811 |
| Density | 2.46 g/cm3 |
| Melting Point | 2075 °C |
| Boiling Point | 4000 °C |
Thermal properties |
| Phase | Solid |
| Melting Point | 2075 °C |
| Boiling Point | 4000 °C |
| Absolute Melting Point | 2348 K |
| Absolute Boiling Point | 4273 K |
| Heat of Fusion | 50 kJ/mol |
| Heat of Vaporization | 507 kJ/mol |
| Heat of Combustion | N/A |
| Specific Heat | 1030 J/(kg K)[note] |
| Thermal Conductivity | 27 W/(m K) |
| Thermal Expansion | 6×10-6 K-1 |
Bulk physical properties |
| Density | 2.46 g/cm3 |
| Density (Liquid) | 2.08 g/cm3 |
| Molar Volume | 4.3947×10-6 |
| Brinell Hardness | N/A |
| Mohs Hardness | 9.3 MPa |
| Vickers Hardness | 4.9×104 MPa |
| Bulk Modulus | 320 GPa |
| Shear Modulus | N/A |
| Young Modulus | N/A |
| Poisson Ratio | N/A |
| Refractive Index | N/A |
| Speed of Sound | 1.62×104 m/s |
| Thermal Conductivity | 27 W/(m K) |
| Thermal Expansion | 6×10-6 K-1 |
Reactivity |
| Valence | 3 |
| Electronegativity | 2.04 |
| ElectronAffinity | 26.7 kJ/mol |
| Ionization Energies | | 800.6, 2427.1, 3659.7, 25025.8, 32826.7 kJ/mol |
|
Health and Safety |
| Autoignition Point | N/A |
| Flashpoint | N/A |
| Heat of Combustion | N/A |
|
Classifications |
| Alternate Names | None |
| Nams of Allotropes | | AlphaRhombohedralBoron, BetaRhombohedralBoron, AlphaTetragonalBoron |
|
| Block | p |
| Group | 13 |
| Period | 2 |
| Electron Configuration | [He]2s22p1 |
| Color | Black |
| Discovery | | 1808 in France and United Kingdom |
|
| Gas phase | N/A |
| CAS Number | CAS7440-42-8 |
Electrical properties |
| Electrical Type | Insulator |
| Electrical Conductivity | 0.0001 S/m |
| Resistivity | 10000 m Ω |
| Superconducting Point | N/A |
Magnetic properties |
| Magnetic Type | Diamagnetic |
| Curie Point | N/A |
| Mass Magnetic Susceptibility | -8.7×10-9 |
| Molar Magnetic Susceptibility | -9.41×10-11 |
| Volume Magnetic Susceptibility | -0.0000214 |
Abundances |
| % in Universe | 1×10-7% |
| % in Sun | 2×10-7% |
| % in Meteorites | 0.00016% |
| % in Earth's Crust | 0.00086% |
| % in Oceans | 0.00044% |
| % in Humans | 0.00007% |
Atomic dimensions and structure |
| Atomic Radius | 87 pm |
| Covalent Radius | 82 pm |
| Van der Waals Radius | N/A |
| Crystal Structure | Simple Trigonal |
| Lattice Angles | | 1.01334, 1.01334, 1.01334 |
|
| Lattice Constants | |
| Space Group Name | R_
3m |
| Space Group Number | 166 |
Nuclear Properties |
| Half-Life | Stable |
| Lifetime | Stable |
| Stable Isotopes | |
| Isotopic Abundances | |
|