Rubidium (Rb)

Rubidium

Symbol	Rb
Atomic Number	37
Atomic Mass	85.4678 g.mol -1
Discovered by	Gustav Kirchhoff and Robert Bunsen

Chemical Properties of Rubidium

Group	1	Melting point	39.30°C, 102.74°F, 312.45 K
Period	5	Boiling point	688°C, 1270°F, 961 K
Block	s	Density (g cm−3)	1.53
Atomic number	37	Relative atomic mass	85.468
State at 20°C	Solid	Key isotopes	85Rb, 87Rb
Electron configuration	[Kr] 5s1	CAS number	7440-17-7
ChemSpider ID	4512975	ChemSpider is a free chemical structure database

What is Rubidium?

• The element is a member of the alkali metal group 1 of the periodic table.
• The element has an atomic number of 37 and an atomic mass of 85.
• The metal is a lithophile metallic element that does not form any minerals of its own.

Uses of Rubidium

• Specialty glasses, which constitute the leading market for rubidium, are used in fiber optics telecommunications systems and in night-vision devices.
• The carbonate (Rb₂CO₃) is used as an additive to these types of glass, where it reduces electrical conductivity and improves stability and durability.
• Rubidium-cesium-antimony coating is commonly applied to the photo-cathodes of photo-multiplier tubes, which are used in radiation detection devices, medical imaging equipment, and night-vision devices.

Properties of Rubidium

• Compared with potassium and sodium, rubidium is relatively rare, with a crustal abundance of just 78 mg kg-1 (Fyfe 1999).
• The Rb+ ion (ionic radius 152 pm) substitutes for K+ (138 pm) in mica such as muscovite and to a lesser extent in K-feldspar such as microcline and orthoclase, as well as rare minerals, such as lepidolite, carnallite, and pollucite, in which it replaces Cs.

Certain Facts About Rubidium

• Used in fireworks to give purple-red color.
• The metal along with strontium is used to date rocks, minerals, and meteorites radioactively.