Ang boro (Iningles boron) mao ang elementong kimiko sa talaang peryodiko nga may simbolo nga B ug kaiphan nga atomik 5. Ang boro mao ang metalloid.
Quick facts Boron, Panagway ...
| Boron |
|---|
5B |
|
|
| Panagway |
black-brown
 |
| Kinatibuk-ang mga kinaiya |
| Ngalan, simbolo, kaiphan |
boron, B, 5 |
| Paglitok |
|
| Kategoriyang elemento |
metalloid |
| Group, period, block |
13, 2, p |
| Gibug-aton sa atomo |
10.81(1) |
| Kontorno sa elektron |
[He] 2s2 2p1
2, 3
 Electron shells of boron (2, 3) |
| History |
| Pagkadiskobre |
Joseph Louis Gay-Lussac and Louis Jacques Thénard[1] (30 June 1808) |
| First isolation |
Humphry Davy[2] (9 July 1808) |
| Physical properties |
| Phase |
magahi |
| Liquid density at m.p. |
2.08 g·cm−3 |
| Melting point |
2349 K, 2076 °C, 3769 °F |
| Boiling point |
4200 K, 3927 °C, 7101 °F |
| Heat of fusion |
50.2 kJ·mol−1 |
| Heat of vaporization |
480 kJ·mol−1 |
| Molar heat capacity |
11.087 J·mol−1·K−1 |
| Vapor 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 |
3, 2, 1[3]
(mildly acidic oxide) |
| Electronegativity |
2.04 (Pauling scale) |
Ionization energies
(more) |
1st: 800.6 kJ·mol−1 |
| 2nd: 2427.1 kJ·mol−1 |
| 3rd: 3659.7 kJ·mol−1 |
| Atomic radius |
90 pm |
| Covalent radius |
84±3 pm |
| Van der Waals radius |
192 pm |
| Miscellanea |
| Crystal structure |
rhombohedral
|
| Magnetic ordering |
diamagnetic[4] |
| Electrical resistivity |
(20 °C) ~106 Ω·m |
| Thermal conductivity |
27.4 W·m−1·K−1 |
| Thermal expansion |
(25 °C) (β form) 5–7[5] µm·m−1·K−1 |
| Speed of sound (thin rod) |
(20 °C) 16,200 m·s−1 |
| Mohs hardness |
~9.5 |
| CAS registry number |
7440-42-8 |
| Most stable isotopes |
| Main article: Isotopes of boron |
| iso |
NA |
half-life |
DM |
DE (MeV) |
DP |
|---|
| 10B |
19.9(7)%* |
10B is stable with 5 neutrons[6] |
| 11B |
80.1(7)%* |
11B is stable with 6 neutrons[6] |
*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.[7] |
|
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