Селен
34
Se
Група
16
Период
4
Блок
p
Протони
Електрони
Неутрони
34
34
45
Главни свойства
Атомен номер
34
Атомна маса
78.96
Масов номер
79
Категория
Неметали
Цвят
Сив
Радиоактивни
Не
From the Greek word Selene, moon
Кристална структура
Просто моноклинично
История
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.
Електрон на обвивка
2, 8, 18, 6
Електронна конфигурация
[Ar] 3d10 4s2 4p4
Selenium deficiency in animals can lead to slow growth
Физични свойства
Фаза
Твърди
Плътност
4.809 g/cm3
Температура на топене
494.15 K | 221 °C | 429.8 °F
Температура на кипене
958.15 K | 685 °C | 1265 °F
Топлина на сливането
5.4 kJ/mol
Топлина на изпаряване
26 kJ/mol
Специфичен топлинен капацитет
0.321 J/g·K
Изобилие в земната кора
5×10-6%
Изобилие в вселената
3×10-6%
![Ultrapure](https://periodic-table.io/images/elements/Se.jpg)
Номер на CAS
7782-49-2
Номер на PubChem CID
6326970
Атомни свойства
Атомен радиус
120 pm
Ковалентен радиус
120 pm
Електроотрицателност
2.55 (Скала на Полинг)
Йонизационен потенциал
9.7524 eV
Моларен обем
16.45 cm3/mol
Топлопроводимост
0.0204 W/cm·K
Оксидационни държави
-2, 2, 4, 6
Приложения
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
Изотопи
Стабилни изотопи
74Se, 76Se, 77Se, 78Se, 80SeНестабилни изотопи
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