Periodic TableAll elementsRubidium
No. 037
Rb
85.468 u
Element · Alkali Metal

Rubidium

Rubidium (铷, symbol Rb) is chemical element number 37, an Alkali Metal in period 5, group 1 of the periodic table, with a standard atomic weight of about 85.468. Soft, silvery-white alkali metal. Used in atomic clocks and specialty glass.

Period 5Group 1[Kr] 5s¹

Properties

Atomic number37
SymbolRb
Atomic mass85.468 u
CategoryAlkali Metal
Period5
Group1
Electron configuration[Kr] 5s¹
Electronegativity0.82
Covalent radius220 pm
Density1.532 g/cm³
Melting point312.46 K
Boiling point961 K
DiscoveryBunsen & Kirchhoff, 1861

Overview

Soft, silvery-white alkali metal. Used in atomic clocks and specialty glass. Element 37, Rubidium (Rb), is an Alkali Metal found in period 5, group 1. As an alkali metal it is soft and highly reactive, releasing hydrogen on contact with water, and is usually stored away from air and moisture.

With 1 electron in its outermost shell, Rubidium bonds accordingly; full configuration [Kr] 5s¹, electronegativity 0.82. At room temperature it is normally a solid (a very low melting point); it melts near 312.46 K (39.3 °C), boils near 961 K (687.9 °C), has a density around 1.532 g/cm³.

Common applications range across Research and Electronics / Semiconductors. On the safety side, it carries a moderate hazard rating. It was first described by Bunsen & Kirchhoff in 1861. See more trends in the visualization center.

Electron shells

Rb37

Electrons per shell: 2 · 8 · 18 · 8 · 1

Main uses

Hazard

ModerateFlammable

Compounds containing Rubidium

No compounds in this knowledge base contain Rubidium yet.

Data sources

Atomic mass uses IUPAC (CIAAW) standard atomic weights; the covalent radius is from Cordero et al. (2008). Verify on the RSC Periodic Table, PubChem and Wikipedia. Educational reference only.