Rubidium
Definition and meaning of Rubidium in chemistry.
Rubidium is an alkali metal chemical element with the symbol Rb and atomic number 37. It is a remarkably soft, silvery-white metallic element that is highly electropositive and stands as one of the most reactive elements on Earth.
In more detail
Positioned in group 1 of the periodic table, rubidium shares the extreme volatility and reactivity common to other heavy alkali metals like potassium and cesium. It oxidizes rapidly and ignites spontaneously in ambient air, and it reacts violently with water to form rubidium hydroxide and hydrogen gas, which immediately catches fire from the heat of the reaction. Because of its tremendous chemical reactivity, it is strictly never found as a free element in nature, but rather occurs scattered in complex minerals such as lepidolite, pollucite, and carnallite. Rubidium has a notably low melting point, meaning it can literally melt into a liquid on a particularly hot day. It effortlessly loses its single valence electron to form the stable Rb+ ion in all of its ionic chemical compounds.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Rb |
| Atomic number | 37 |
| Atomic mass | 85.468 u |
| Category | Alkali Metal |
| State at room temperature | Solid |
| Melting point | 39.3 degrees Celsius |
| Boiling point | 688 degrees Celsius |
| Discoverers | Robert Bunsen and Gustav Kirchhoff (1861) |
Rubidium is strategically used in the specialized manufacture of specific glasses for fiber optic telecommunications systems, in the production of photocells, and in the highly precise oscillators of some atomic clocks.
Frequently asked questions
How must elemental rubidium be stored to prevent explosions?
Because it reacts so vigorously with moisture and oxygen in the air, pure rubidium must be meticulously stored completely submerged in a dry mineral oil or sealed within a glass ampoule containing an inert atmosphere like argon.
Is natural rubidium considered a radioactive material?
Natural rubidium is composed of two isotopes, one of which is stable and the other, rubidium-87, is slightly radioactive with an exceptionally long half-life of nearly 49 billion years.