Selenium

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Selenium
34Se
S

Se

Te
arsenicseleniumbromine
Ìhànsójú
Black, gray, and red allotropes
Àwọn ìdámọ́ wíwọ́pọ̀
Orúkọ, àmì-ìdámọ́, nọ́mbà selenium, Se, 34
Ẹ̀ka ẹ́límẹ̀nti nonmetal
Ẹgbẹ́, àsìkò, àdìpò 164, p
Ìwúwo átọ́mù 78.96
Ìtòléra ẹ̀lẹ́ktrónì [Ar] 4s2 3d10 4p4
2, 8, 18, 6
Physical properties
Phase solid
Density (near r.t.) (gray) 4.81 g·cm−3
Density (near r.t.) (alpha) 4.39 g·cm−3
Density (near r.t.) (vitreous) 4.28 g·cm−3
Liquid density at m.p. 3.99 g·cm−3
Melting point 494 K, 221 °C, 430 °F
Boiling point 958 K, 685 °C, 1265 °F
Critical point 1766 K, 27.2 MPa
Heat of fusion (gray) 6.69 kJ·mol−1
Heat of vaporization 95.48 kJ·mol−1
Molar heat capacity 25.363 J·mol−1·K−1
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 500 552 617 704 813 958
Atomic properties
Oxidation states 6, 4, 2, 1,[1] -2
(strongly acidic oxide)
Electronegativity 2.55 (Pauling scale)
Ionization energies 1st: 941.0 kJ·mol−1
2nd: 2045 kJ·mol−1
3rd: 2973.7 kJ·mol−1
Atomic radius 120 pm
Covalent radius 120±4 pm
Van der Waals radius 190 pm
Miscellanea
Crystal structure hexagonal
Selenium has a hexagonal crystal structure
Magnetic ordering diamagnetic[2]
Thermal conductivity (amorphous) 0.519 W·m−1·K−1
Thermal expansion (25 °C) (amorphous) 37 µm·m−1·K−1
Speed of sound (thin rod) (20 °C) 3350 m·s−1
Young's modulus 10 GPa
Shear modulus 3.7 GPa
Bulk modulus 8.3 GPa
Poisson ratio 0.33
Mohs hardness 2.0
Brinell hardness 736 MPa
CAS registry number 7782-49-2
Àwọn ísótòpù dídúró jùlọ
Main article: Àwọn ísótòpù selenium
iso NA half-life DM DE (MeV) DP
72Se syn 8.4 d ε - 72As
γ 0.046 -
74Se 0.87% 74Se is stable with 40 neutrons
75Se syn 119.779 d ε - 75As
γ 0.264, 0.136,
0.279
-
76Se 9.36% 76Se is stable with 42 neutrons
77Se 7.63% 77Se is stable with 43 neutrons
78Se 23.78% 78Se is stable with 44 neutrons
79Se trace 2.95×105 y β 0.151 79Br
80Se 49.61% 80Se is stable with 46 neutrons
82Se 8.73% 1.08×1020 y ββ 2.995 82Kr
· r



Itokasi[àtúnṣe | àtúnṣe àmìọ̀rọ̀]

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  2. Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics 81st edition, CRC press.