| Selenium |
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34Se |
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| Panagway |
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black and red allotropes
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| Kinatibuk-ang mga kinaiya |
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| Ngalan,simbolo,kaiphan | selenium, Se, 34 |
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| Paglitok | /sᵻˈliːniəm/[[Help:Pronunciation respelling key|si-Plantilya:Smallcaps all-nee-əm]] |
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| Kategoriyang elemento | wala puthaw
sometimes considered ametalloid |
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| Group,period,block | 16, 4,p |
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| Gibug-aton sa atomo | 78.96 |
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| Kontorno sa elektron | [Ar] 3d10 4s2 4p4
2, 8, 18, 6 Electron shells of selenium (2, 8, 18, 6) |
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| History |
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| Pagkadiskobre | Jöns Jakob Berzelius andJohann Gottlieb Gahn (1817) |
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| First isolation | Jöns Jakob Berzelius and Johann Gottlieb Gahn (1817) |
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| Physical properties |
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| Phase | magahi |
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| Density (nearr.t.) | (gray) 4.81 g·cm−3 |
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| Density (nearr.t.) | (alpha) 4.39 g·cm−3 |
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| Density (nearr.t.) | (vitreous) 4.28 g·cm−3 |
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| Liquiddensity atm.p. | 3.99 g·cm−3 |
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| Melting point | 494 K, 221 °C, 430 °F |
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| Boiling point | 958 K, 685 °C, 1265 °F |
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| Critical point | 1766 K, 27.2 MPa |
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| Heat of fusion | (gray) 6.69kJ·mol−1 |
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| Heat of vaporization | 95.48 kJ·mol−1 |
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| Molar heat capacity | 25.363 J·mol−1·K−1 |
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| Vapor pressure |
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| P (Pa) | 1 | 10 | 100 | 1 k | 10 k | 100 k | | at T (K) | 500 | 552 | 617 | 704 | 813 | 958 |
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| Atomic properties |
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| Oxidation states | 6,4,2, 1,[1] -2
(stronglyacidic oxide) |
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| Electronegativity | 2.55 (Pauling scale) |
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| Ionization energies | 1st: 941.0 kJ·mol−1 |
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| 2nd: 2045 kJ·mol−1 |
| 3rd: 2973.7 kJ·mol−1 |
| Atomic radius | 120pm |
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| Covalent radius | 120±4 pm |
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| Van der Waals radius | 190 pm |
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| Miscellanea |
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| Crystal structure | hexagonal |
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| Magnetic ordering | diamagnetic[2] |
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| Thermal conductivity | (amorphous) 0.519 W·m−1·K−1 |
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| Thermal expansion | (25 °C) (amorphous) 37 µm·m−1·K−1 |
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| Speed of sound (thin rod) | (20 °C) 3350 m·s−1 |
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| Young's modulus | 10 GPa |
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| Shear modulus | 3.7 GPa |
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| Bulk modulus | 8.3 GPa |
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| Poisson ratio | 0.33 |
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| Mohs hardness | 2.0 |
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| Brinell hardness | 736 MPa |
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| CAS registry number | 7782-49-2 |
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| Most stable isotopes |
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| Main article:Isotopes of selenium |
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| ·r |
