Boron
Boron, 5B
boron (β-rhombohedral)
|
| General properties |
| Name, symbol
|
boron, B |
| Pronunciation |
|
| Allotropes |
α-, β-rhombohedral, β-tetragonal (and more) |
| Appearance |
black-brown |
|
| Boron in the periodic table
|
|
|
| Atomic number (Z) |
5 |
|
Group, block
|
group 13 (boron group), p-block
|
| Period |
period 2 |
| Element category |
metalloid
|
|
Standard atomic weight (Ar)
|
10.81 (10.806–10.821) |
| Electron configuration |
[He] 2s2 2p1
|
|
per shell
|
2, 3 |
| Physical properties |
| Phase |
solid |
| Melting point |
2349 K (2076 °C, 3769 °F) |
| Boiling point |
4200 K (3927 °C, 7101 °F) |
|
Density when liquid, at m.p.
|
2.08 g/cm3
|
| Heat of fusion |
50.2 kJ/mol
|
| Heat of vaporization |
508 kJ/mol |
| Molar heat capacity |
11.087 J/(mol·K) |
Vapor pressure
|
P (Pa)
|
1 |
10 |
100 |
1 k |
10 k |
100 k |
| at T (K)
|
2348 |
2562 |
2822 |
3141 |
3545 |
4072 |
|
| Wikipedia
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