Selen
34
Se
Gruppe
16
Periode
4
Blokk
p
Protons
Electrons
Neutrons
34
34
45
Generelle eigenskapar
Atomnummer
34
Atommasse
78,96
Mass Number
79
Kategori
Ikkje-metall
Farge
Grå
Radioactive
Nei
From the Greek word Selene, moon
Krystallstruktur
Simple Monoclinic
Historie
Selenium was first observed in about the year 1300 by the alchemist Arnold of Villanova.
Selenium was discovered in 1817 by Jöns Jacob Berzelius and Johan Gottlieb Gahn who noted the similarity of the new element to the previously-known tellurium.
In 1873, Willoughby Smith found that the electrical resistance of grey selenium was dependent on the ambient light.
Selenium was discovered in 1817 by Jöns Jacob Berzelius and Johan Gottlieb Gahn who noted the similarity of the new element to the previously-known tellurium.
In 1873, Willoughby Smith found that the electrical resistance of grey selenium was dependent on the ambient light.
Elektron per energinivå
2, 8, 18, 6
Elektronkonfigurasjon
[Ar] 3d10 4s2 4p4
Selenium deficiency in animals can lead to slow growth
Fysiske eigenskapar
Tilstandsform
Fast stoff
Tettleik
4,809 g/cm3
Smeltepunkt
494,15 K | 221 °C | 429,8 °F
Kokepunkt
958,15 K | 685 °C | 1265 °F
Smeltevarme
5,4 kJ/mol
Fordampingsvarme
26 kJ/mol
Spesifikk varmekapasitet
0,321 J/g·K
Abundance in Earth's crust
5×10-6%
Abundance in Universe
3×10-6%
CAS Number
7782-49-2
PubChem CID Number
6326970
Atom eigenskapar
Atomradius
120 pm
Kovalent radius
120 pm
Elektronegativitet
2,55 (Paulings skala)
Ioniseringspotensial
9,7524 eV
Molart volum
16,45 cm3/mol
Termisk konduktivitet
0,0204 W/cm·K
Oksidasjonstrinn
-2, 2, 4, 6
Applications
Selenium is used in the glass industry to decolorize glass and to make red-colored glasses and enamels.
It is used as a catalyst in many chemical reactions.
It is also used as a photographic toner, and as an additive to stainless steel.
Selenium sulfide is used in anti-dandruff shampoos.
It is used as a catalyst in many chemical reactions.
It is also used as a photographic toner, and as an additive to stainless steel.
Selenium sulfide is used in anti-dandruff shampoos.
Many of selenium's compounds, such as selenates and selenites, are highly toxic
Isotopes
Stable Isotopes
74Se, 76Se, 77Se, 78Se, 80SeUnstable Isotopes
65Se, 66Se, 67Se, 68Se, 69Se, 70Se, 71Se, 72Se, 73Se, 75Se, 79Se, 81Se, 82Se, 83Se, 84Se, 85Se, 86Se, 87Se, 88Se, 89Se, 90Se, 91Se, 92Se, 93Se, 94Se