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Boron,5 👁 Image boron (β-rhombohedral)
[ 1] Boron Pronunciation /ˈ b ɔːr ɒ n (BOR -on Appearance black-broun Standard atomic weight A r,std (B)[7001108059999999999♠ 10.8067001108210000000000♠ 10.8217001108100000000000♠ 10.81 Boron in the periodic cairt
Atomic nummer (Z ) 5 Group group13 (boron group) Period period2 Block p-block Element category Metalloid Electron confeeguration [ He ] 2s2 2p1 Electrons per shell 2, 3 Pheesical properties Phase atSTP solit Meltinpynt 2349K (2076°C, 3769°F) Bylinpynt 4200K (3927°C, 7101°F) Density whenliquid (atm.p. ) 2.08g/cm3 Heatofusion 50.2kJ/mol Heat o vapourisation 480kJ/mol Molar heat capacity 11.087J/(mol·K) Vapourpressur
P (Pa) 1
10
100
1k
10k
100k
atT (K)
2348
2562
2822
3141
3545
4072
Atomic properties Oxidation states −5, −1, 0,[ 2] +3 [ 3] [ 4] acidic oxide) Electronegativity Paulingscale: 2.04 Ionisation energies Atomic radius empirical:90 pm Covalent radius 84±3 pmVan der Waals radius 192 pm👁 Colour lines in a spectral range Colour lines in a spectral range Spectral lines o boronIther properties Naitural occurrence primordial Creestal structur rhombohedral Speed o soond thinrod 16,200m/s(at20°C) Thermal expansion (β form) 5– 7[ 5] Thermal conductivity 27.4W/(m·K) Electrical resistivity ~106 Ω·m(at20°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 symbolB an atomic nummer 5. Acause boron is produced entirely bi cosmic ray spallation an nae bi stellar nucleosynthesis ,[ 11] 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. 1 2 "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 . ↑ "Q & A: Where does the element Boron come from?" . physics.illinois.edu . Archived frae the original on 29 Mey 2012. Retrieved 4 December 2011 .
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