# Bórọ̀nù

Bórọ̀nù, 5B| boron (β-rhombohedral) |
| Bórọ̀nù |
| Pípè |  /ˈbɔːrɒn/ ​(*BOR-on*) |
| Ìhànsójú | black-brown |
| Ìwúwo átọ̀mù *A*r, std(B) | [10.806, 10.821] conventional: 10.81 |
| Bórọ̀nù ní orí tábìlì àyè |
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|  |  |  |
| --- | --- | --- |
| Hydrogen |  | Helium |
| Lithium | Beryllium |  | Boron | Carbon | Nitrogen | Oxygen | Fluorine | Neon |
| Sodium | Magnesium |  | Aluminium | Silicon | Phosphorus | Sulfur | Chlorine | Argon |
| Potassium | Calcium | Scandium |  | Titanium | Vanadium | Chromium | Manganese | Iron | Cobalt | Nickel | Copper | Zinc | Gallium | Germanium | Arsenic | Selenium | Bromine | Krypton |
| Rubidium | Strontium | Yttrium |  |  | Zirconium | Niobium | Molybdenum | Technetium | Ruthenium | Rhodium | Palladium | Silver | Cadmium | Indium | Tin | Antimony | Tellurium | Iodine | Xenon |
| Caesium | Barium | Lanthanum | Cerium | Praseodymium | Neodymium | Promethium | Samarium | Europium | Gadolinium | Terbium | Dysprosium | Holmium | Erbium | Thulium | Ytterbium | Lutetium | Hafnium | Tantalum | Tungsten | Rhenium | Osmium | Iridium | Platinum | Gold | Mercury (element) | Thallium | Lead | Bismuth | Polonium | Astatine | Radon |
| Francium | Radium | Actinium | Thorium | Protactinium | Uranium | Neptunium | Plutonium | Americium | Curium | Berkelium | Californium | Einsteinium | Fermium | Mendelevium | Nobelium | Lawrencium | Rutherfordium | Dubnium | Seaborgium | Bohrium | Hassium | Meitnerium | Darmstadtium | Roentgenium | Copernicium | Nihonium | Flerovium | Moscovium | Livermorium | Tennessine | Oganesson |

 | - ↑ **B** ↓ Al |
| bẹ́rílíọ̀mù ← **bórọ̀nù** → kárbọ̀nù |

 |

 |
| Nọ́mbà átọ̀mù (*Z*) | 5 |
| Ẹgbẹ́ | group 13 (boron group) |
| Àyè | àyè 2  |
| Àdìpọ̀ | Àdìpọ̀-p  |
| Ẹ̀ka ẹ́límẹ́ntì |   Metalloid |
| Ìtò ẹ̀lẹ́ktrọ́nù | [He] 2s2 2p1 |
| Iye ẹ̀lẹ́ktrọ́nù lórí ìpele kọ̀ọ̀kan | 2, 3 |
| Àwọn ohun ìní ara |
| Ìfarahàn at STP | aláralíle |
| Ìgbà ìyọ́ | 2349 K ​(2076 °C, ​3769 °F)  |
| Ígbà ìhó | 4200 K ​(3927 °C, ​7101 °F)  |
| Kíki when liquid (at m.p.) | 2.08 g/cm3  |
| Heat of fusion | 50.2 kJ/mol  |
| Heat of  | 480 kJ/mol  |
| Molar heat capacity | 11.087 J/(mol·K)  |
| **pressure**

| *P* (Pa) | 1 | 10 | 100 | 1 k | 10 k | 100 k |
| --- | --- | --- | --- | --- | --- | --- |
| at *T* (K) | 2348 | 2562 | 2822 | 3141 | 3545 | 4072 |

 |
| Atomic properties |
| Oxidation states | −5, −1, 0, +1, +2, **+3** Àdàkọ:Infobox element/symbol-to-oxidation-state/comment |
| Electronegativity | Pauling scale: 2.04  |
|  energies | * (more)
 |
| Atomic radius | empirical: 90 pm  |
| Covalent radius | 84±3 pm  |
| Van der Waals radius | 192 pm  |
| Color lines in a spectral range**Spectral lines of bórọ̀nù** |
| Other properties |
| Natural occurrence | primordial |
| Crystal structure |  ​rhombohedral |
| Speed of sound  thin rod | 16,200 m/s (at 20 °C)  |
| Thermal expansion | (β form) 5–7 µm/(m·K) (at 25 °C)  |
| Thermal conductivity | 27.4 W/(m·K)  |
| Electrical resistivity | ~106  Ω·m (at 20 °C)  |
| Magnetic ordering | diamagnetic  |
| Mohs hardness | ~9.5  |
| CAS Number | 7440-42-8  |
| History |
| Discovery | Joseph Louis Gay-Lussac and Louis Jacques Thénard (30 June 1808) |
| First isolation | Humphry Davy (9 July 1808) |
| Main isotopes of bórọ̀nù |
|

| Iso­tope | Abun­dance | Half-life (*t*1/2) | Decay mode | Pro­duct |
| --- | --- | --- | --- | --- |
| 10B | 19.9(7)%\* | 10B is stable with 5 neutrons |
| 11B | 80.1(7)%\* | 11B is stable with 6 neutrons |

 |
| * Boron-10 content may be as low as 19.1% and as high as 20.3% in natural samples. Boron-11 is the remainder in such cases.
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**Bórọ̀nù** ni ẹ́límẹ̀ntì kẹ́míkà kan tó ní àmì-ìdámọ̀ **B** àti nọ́mbà átọ̀mù 5. Nítorípé bórọ̀nù jẹ́ dídá pátápátá pẹ̀lu ìtúká ìrànká kọ́smíkì tí kò sì jẹ́ pẹ̀lù núkléùkíkódájọpọ̀ oníràwọ̀, kò fi bẹ́ẹ̀ pọ̀ ní inú sístẹ́mù òrùn àti nínú ìgbẹ́lẹ̀ Ayé. Bórọ̀nù wọ́jọ ní Ayé pẹ̀lu ìtúsómi àwọn àdàpọ̀ rẹ̀ tí wọ́n wọ́pọ̀, èyun ùn àwọn àlùmọ́nì bóràtì. Àwọn wọ̀nyí únjẹ́ wíwà láti inú ilẹ̀ ní ilé-iṣẹ́ gẹ́gẹ́bí ìṣágbẹ, bíi bóráksì àti kẹ́rnítì.

Bórọ̀nù
Bórọ̀nú, tó jẹ́ títòpọ̀ mọ́ ẹgbẹ́ mẹ́tálọ́ìdì, tí kò darapọ̀ bíi kẹ́míkà kò sí ní Ilé-Ayé. Ní ilé-iṣẹ́, ó ṣòro látí dá bórọ̀nù ògidì nítorípé oúndá èròjà míràn tí wọ́n ní kárbọ́nù tàbí àwọn ẹ́límẹ̀ntí míràn díẹ̀ nínú. Orísi àwọn àllótrópù bórọ̀nù lówà: bórọ̀nù amorphous boron is a brown powder and crystalline boron is black, extremely hard (about 9.5 on the Mohs scale), and a poor conductor at room temperature. Elemental boron is used as a dopant in the semiconductor industry.

## Itokasi