Boro

Boron
5B
- ↑ B ↓ Al Periodic table beryllium ← boron → carbon
Panagway
black-brown
Kinatibuk-ang mga kinaiya
Ngalan, simbolo, kaiphan	boron, B, 5
Paglitok	/ˈbɔərɒn/
Kategoriyang elemento	metalloid
Group, period, block	13, 2, p
Gibug-aton sa atomo	10.81(1)
Kontorno sa elektron	[He] 2s2 2p1 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]
v t e · r

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.

1. ↑ Gay Lussac, J.L. and Thenard, L.J. (1808) "Sur la décomposition et la recomposition de l'acide boracique," Annales de chimie [later: Annales de chemie et de physique], vol. 68, pp. 169–174.
2. ↑ Davy H (1809). "An account of some new analytical researches on the nature of certain bodies, particularly the alkalies, phosphorus, sulphur, carbonaceous matter, and the acids hitherto undecomposed: with some general observations on chemical theory". Philosophical Transactions of the Royal Society of London. 99: 33–104.
3. ↑ Zhang, K.Q.; Guo, B.; Braun, V.; Dulick, M.; Bernath, P.F. (1995). "Infrared Emission Spectroscopy of BF and AIF" (PDF). J. Molecular Spectroscopy. 170: 82. Bibcode:1995JMoSp.170...82Z. doi:10.1006/jmsp.1995.1058.{{cite journal}}: CS1 maint: multiple names: authors list (link)
4. ↑ Lide, David R. (ed.) (2000). Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics (PDF). CRC press. ISBN 0849304814. {{cite book}}: |author= has generic name (help)
5. ↑ Holcombe Jr., C. E.; Smith, D. D.; Lorc, J. D.; Duerlesen, W. K.; Carpenter; D. A. (October 1973). "Physical-Chemical Properties of beta-Rhombohedral Boron". High Temp. Sci. 5 (5): 349–57.{{cite journal}}: CS1 maint: multiple names: authors list (link)
6. ↑ ^{6.0 6.1} "Atomic Weights and Isotopic Compositions for All Elements". National Institute of Standards and Technology. Retrieved 2008-09-21.
7. ↑ Szegedi, S.; Váradi, M.; Buczkó, Cs. M.; Várnagy, M.; Sztaricskai, T. (1990). "Determination of boron in glass by neutron transmission method". Journal of Radioanalytical and Nuclear Chemistry Letters. 146 (3): 177. doi:10.1007/BF02165219.