Rb
85.468Rubidium
Rubidyum
Rubidium is a soft, highly reactive alkali metal with atomic number 37. It is known for atomic clocks, spectroscopy, rubidium-strontium dating, Bose-Einstein condensate research and specialized glass or vacuum applications.
37
85.468 g/mol
[Kr] 5s¹
2 | 8 | 18 | 8 | 1
0.82
1.532 g/cm³
39.31 °C
687.9 °C
Robert Bunsen
Rubidium was discovered in 1861 by Robert Bunsen and Gustav Kirchhoff using spectroscopy. Its name comes from the Latin rubidus, meaning deep red, referring to its spectral lines.
Rubidium-85
Natural abundance: About 72.2%. The most abundant stable isotope of rubidium.Rubidium-87
Natural abundance: About 27.83%. Half-life: About 4.97 x 10¹⁰ years. Long-lived radioactive isotope used in Rb-Sr dating.Rubidium-82
Natural abundance: Synthetic. Half-life: About 75 seconds. Positron-emitting isotope used in cardiac PET imaging.RbCl
Rubidium ChlorideResearch reagent and rubidium source in biological and chemical studies.RbOH
Rubidium HydroxideStrong base used in specialized rubidium chemistry.Rb₂CO₃
Rubidium CarbonateSpecialty glass additive and rubidium compound precursor.RbNO₃
Rubidium NitrateOxidizer and specialty pyrotechnic chemical producing violet-red colors.- Rubidium atomic clocks and frequency standards
- Rubidium vapor cells in magnetometers and physics experiments
- Rubidium-strontium dating using the decay of rubidium-87
- Specialty glass and photocathode research
- Rubidium-82 PET imaging for cardiac blood-flow studies
Rubidium has no confirmed essential biological role. Rb⁺ resembles K⁺ chemically, so rubidium can sometimes follow potassium pathways in biological and medical tracer contexts.
- Rubidium is much more reactive than potassium and can ignite in air or react violently with water.
- Rubidium-87 decays to strontium-87, enabling Rb-Sr radiometric dating.
- Rubidium atomic clocks are compact frequency standards used in telecommunications and navigation systems.
- Rubidium atoms were used in landmark Bose-Einstein condensate experiments.
- Rubidium has atomic number 37 and belongs to group 1, the alkali metals.
- Its electron configuration is [Kr] 5s¹.
- Rubidium commonly forms Rb⁺ by losing one valence electron.
- Alkali metal reactivity generally increases down the group, so rubidium is more reactive than potassium.
What is the atomic number of rubidium?
The atomic number of rubidium is 37.
What is the electron configuration of rubidium?
Rubidium has the electron configuration [Kr] 5s¹.
What is rubidium used for?
Rubidium is used in atomic clocks, vapor-cell instruments, Rb-Sr dating, specialty glass, research and rubidium-82 PET imaging.
What is rubidium-strontium dating?
Rubidium-strontium dating uses the decay of rubidium-87 to strontium-87 to estimate ages of rocks and minerals.
Why is rubidium used in atomic clocks?
Rubidium has stable microwave transitions that can serve as compact frequency standards.
Is rubidium reactive with water?
Yes. Rubidium reacts very vigorously with water to form rubidium hydroxide and hydrogen gas.