Rb
Rubidium
RUBIDIUM
ALKALI METAL
| Atomic number: | 37 |
| Group numbers: | 1 |
| Period: | 5 |
| Electronic configuration: | [Kr] 5s1 |
| Formal oxidation number: | +1 |
| Electronegativities: | 0.82 |
| Atomic radius / pm: | 247.5 |
| Relative atomic mass: | 85.4678(3) |
Rubidium was discovered by Robert Wilhelm Bunsen and Gustav Robert Kirchhoff (DE) in 1861. The origin of the name comes from the Latin word rubidius meaning dark red or deepest red. It is a soft, silvery-white, highly reactive metal that ignites in air and reacts violently with water or oxidants. Rubidium occurs abundantly, but so widespread that production is limited. It is usually obtained from lithium production. It is used in photocells, cathode-ray and vacuum tubes, and as a catalyst. The price of 99.8 % pure rubidium metal is 1669.80 € for 100 g.
| Density / g dm-3: | 1532 | (293 K) |
| 1475 | (m.p.) | |
| Molar volume / cm3mol-1: | 55.79 | (293 K) |
| 57.94 | (m.p.) | |
| Electrical resistivity / µΩcm: | 12.5 | (20 °C) |
| Thermal conductivity / W m-1K-1: | 52.8 |
| Melting point / °C: | 39.31 |
| Boiling point / °C: | 688 |
| Heat of fusion / kJ mol-1: | 2.2 |
| Heat of vaporization / kJ mol-1: | 75.7 |
| Heat of atomization / kJ mol-1: | 82.17 |
| First ionization energy / kJ mol-1: | 403.03 |
| Second ionization energy / kJ mol-1: | 2632.62 |
| Third ionization energy / kJ mol-1: | 3859.44 |
| in the atmosphere / ppm: | - |
| in the Earth's crust / ppm: | 32 |
| in the oceans / ppm: | 0.12 |
| Crystal structure: | body-centered cubic |
| Unit-cell dimensions / pm: | a=562 |
| Space group: | Im3m |
| Isotope | Relative atomic mass | Mass percent (%) |
|---|---|---|
| 85Rb | 84.911789(3) | 72.165(20) |
| 87Rb | 86.909183(3) | 27.835(20) |
| Balanced half-reaction | Eo / V | |
|---|---|---|
| Rb+ + e- → Rb(s) | - 2.93 |
| 36 Krypton | ← | 37 Rubidium | → | 38 Strontium |
Citing this page:
Generalic, Eni. "Rubidium." EniG. Periodic Table of the Elements. KTF-Split, 18 Jan. 2024. Web. {Date of access}. <https://www.periodni.com/rb.html>.
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