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Atomic Number
|
Electron configuration
|
Oxidation numbers
|
Atomic Weight | |
| Boron (B) | 5 | [He] 2s2 2p1 | +2, +3 | 10.81 |
| Aluminum (Al) | 13 | [Ne] 3s23p1 | +3 | 26.98 |
| Gallium (Ga) | 31 | [Ar] 3d104S24p | +3 | 69.72 |
| Indium (In) | 49 | [Kr] 4d105s25p | +3 | 114.82 |
| Thallium (Tl) | 81 | [Xe] 4f145d106s26p | +1, +3 | 204.37 |
|
Atomic Number
|
Electron configuration
|
Oxidation numbers
|
Atomic Weight | |
| Boron (B) | 5 | [He] 2s2 2p1 | +2, +3 | 10.81 |
The main natural source of boron is borax (Sodium tetraborate): Na2B4O7 . 10 H2O.
The most common oxidation number of boron is +3 as in the following compounds:
| boron (III) fluoride: BF3 | Borinic acids: R2BOH | Boronic acids: RB(OH)2 |
Boranes are volatile boron hydrides, the most simple is diborane B2H6.
Borohydrides: contain the ion BH4-. For example, Sodium Borohydride: (NaBH4), Aluminum Borohydride: Al(BH4)3.
Boric acid is the hydrated form of B2O3 (boron trioxide), despite its formula boric acid is a monobasic quite weak acid and its acidity is due to the reaction:
B(OH)3 + H2O = B(OH)4- + H+
In other words, boric acid is a Lewis acid which accepts electrons from OH- thus liberating an hyrogenion. Salts of boric acid (e.g., Sodium borate: Na3BO3) are quite complicated compounds which at least in acqueous solutions never contain the simple anion BO3-3.
Some compounds are known in which the formal oxidation state of boron is +2:
|
boron (II) fluoride: B2F4
|
boron (II) chloride: B2Cl4
|
Bauxite: Al2O3