césium
- Domaine
-
- chimiechimie minérale
- Date
Définition :
Métal argenté mou largement utilisé dans les appareillages photoélectriques à cause de sa grande sensibilité à la lumière.
Notes :
Emplois : cellules photoélectriques; tubes de radio; getter dans les tubes à vide.
Il a un usage possible pour la propulsion ionique à faible poussée pour les engins spatiaux.
Termes :
- césium n. m.
- Cs
- caesium n. m.
Traductions
-
anglais
Date :Notes :
An element. State: liquid; group: ia; atomic no.: 55; atomic wt.: 132.9055; valence: 1. Cesium has a notably low melting point, 28.5 °C (83 °F), and is one of the three elements that are liquid at room temperature; it is classified as an alkali metal and is in the same group as sodium and potassium. It is intensely reactive with oxygen and members of the halogen group, causing ignition, and with sulfur and phosphorus it reacts explosively. Thus, it must be protected from contact with air by storage in sealed bottles or steel cylinders.
Early uses of cesium were in photoelectric cells and as a getter in vacuum-tubes; more recently its power-generating ability has been studied for possible thermoelectric applications, especially for spacecraft. Cesium has only one stable form.Termes :
- cesium
- Cs
- caesium
[Cs] Symbol for the element cesium, the name being derived from the latin for blue, the frequency of its spectral lines.