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Boron, 5 B boron (β-rhombohedral)
[ 1] Boron Pronunciation (BOR -on ) Appearance black-broun Standard atomic weight A r, std (B) [7001108059999999999♠ 10.806 , 7001108210000000000♠ 10.821 ] conventional: 7001108100000000000♠ 10.81 Boron in the periodic cairt
Atomic nummer (Z ) 5 Group group 13 (boron group) Period period 2 Block p-block Element category Metalloid Electron confeeguration [He ] 2s2 2p1 Electrons per shell 2, 3 Pheesical properties Phase at STP solit Meltin pynt 2349 K (2076 °C, 3769 °F) Bylin pynt 4200 K (3927 °C, 7101 °F) Density when liquid (at m.p. ) 2.08 g/cm3 Heat o fusion 50.2 kJ/mol Heat o vapourisation 480 kJ/mol Molar heat capacity 11.087 J/(mol·K) Vapour pressur
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,[ 2] +1, +2, +3 [ 3] [ 4] (a mildly acidic oxide) Electronegativity Pauling scale: 2.04 Ionisation energies Atomic radius empirical: 90 pm Covalent radius 84±3 pm Van der Waals radius 192 pm Colour lines in a spectral range Spectral lines o boronIther properties Naitural occurrence primordial Creestal structur rhombohedral Speed o soond thin rod 16,200 m/s (at 20 °C) Thermal expansion (β form) 5–7[ 5] µm/(m·K) (at 25 °C) Thermal conductivity 27.4 W/(m·K) Electrical resistivity ~106 Ω·m (at 20 °C) Magnetic orderin diamagnetic [ 6] Mohs haurdness ~9.5 CAS Nummer 7440-42-8 History Diskivery Joseph Louis Gay-Lussac an Louis Jacques Thénard [ 7] (30 June 1808) First isolation Humphry Davy [ 8] (9 Julie 1808) Main isotopes o boron
10 B content may be as low as 19.1% and as high as 20.3% in natural samples. 11 B is the remainder in such cases.[ 10] | references
Boron is a chemical element wi symbol B an atomic nummer 5. Acause boron is produced entirely bi cosmic ray spallation an nae bi stellar nucleosynthesis ,[ 12] it is a law-abundance element in baith the solar seestem an the Yird's crust. Boron is concentratit on Yird bi the watter-solubility o its mair common naiturally occurrin compoonds, the borate minerals . Thir are mined industrially as evaporites , sic as borax an kernite .
↑ Van Setten et al. 2007, pp. 2460–1
↑ Braunschweig, H.; Dewhurst, R. D.; Hammond, K.; Mies, J.; Radacki, K.; Vargas, A. (2012). "Ambient-Temperature Isolation of a Compound with a Boron-Boron Triple Bond". Science . 336 (6087): 1420–2. Bibcode :2012Sci...336.1420B . doi :10.1126/science.1221138 . PMID 22700924 .
↑ Zhang, K.Q.; Guo, B.; Braun, V.; Dulick, M.; Bernath, P.F. (1995). "Infrared Emission Spectroscopy of BF and AIF" (PDF) . J. Molecular Spectroscopy (in Inglis). 170 (1): 82. Bibcode :1995JMoSp.170...82Z . doi :10.1006/jmsp.1995.1058 .
↑ Melanie Schroeder. "Eigenschaften von borreichen Boriden und Scandium-Aluminium-Oxid-Carbiden" (PDF) (in German). p. 139.
↑ 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. CS1 maint: multiple names: authors leet (link )
↑ Lide, David R. (ed.) (2000). Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics (PDF) . CRC press. ISBN 0849304814 . CS1 maint: extra text: authors leet (link )
↑ 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.
↑ 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.
↑ a b "Atomic Weights and Isotopic Compositions for All Elements" . National Institute of Standards and Technology. Retrieved 21 September 2008 .
↑ 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 .
↑ 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 . CS1 maint: multiple names: authors leet (link )
↑ "Q & A: Where does the element Boron come from?" . physics.illinois.edu . Archived frae the original on 29 Mey 2012. Retrieved 4 December 2011 .