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Rubidium 37Rb85.47
Discovered in 1861 by R.W. Bunsen and G. Kirchhoff at the University of Heidelberg, Germany.
[Latin: rubidius = deepest red]
French: rubidium
German: Rubidium
Italian: rubidio
Spanish: rubidio
Description: Rubidium is a
soft, white, metal which is silvery when first cut but it oxidises rapidly in
air and ignites. It reacts violently with water. Rubidium is obtained by the
reaction of calcium or potassium metal with rubidium chloride. The metal and its
compounds are rarely used commercially, and only a little is used for research purposes.
Materials properties
| Density: |
1532 kg/m-3 [293 K]; 1475 [liquid at m.p.] |
| Melting point: |
312.2 °K |
| Boiling point: |
961 °K |
| Molar volume: |
55.79 cm3 |
| Thermal conductivity: |
58.2 [300 K] Wm-1K-1 |
| Coefficient of linear thermal expansion: |
90 x 10-6 K-1 |
| Electrical resistivity: |
12.5 x 10-8 [293 K] Wm |
| Mass magnetic susceptibility: |
+2.49 x 10-9(s) kg-1m3 |
| Young's modulus: |
2.35 GPa |
| Rigidity modulus: |
0.91 GPa |
| Bulk modulus: |
n.a. |
| Poisson's ratio: |
0.30 GPa |
| Radii: |
Rb+ 149; atomic 247.5; van der Waals 244 |
| Electronegativity: |
0.82 (Pauling); 0.89 (Allred); 2.34 eV (absolute) |
| Effective nuclear charge: |
2.20 (Slater); 4.98 (Clementi); 6.66 (Froese-Fischer) |
| Number of Isotopes (incl. nuclear isomers): |
30 |
| Issotope mass range: |
75 -> 98 |
Biological data
| Biological role: |
Rubidium has no known role; its salts have a stimulatory effect. |
| Toxicity |
|
| Toxic intake: |
can be toxic by ingestion |
| Lethal intake: |
LD50 (chloride, oral, mouse) = 3800 mg kg-1 |
| Hazards: |
Rubidium salts are generally inert, and their toxicity is almost always that of the anion, not of the Rb+. However, in the body, rubidium substitutes for potassium and too much can be dangerous.
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| Level in humans |
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| Blood: |
2.49 mg dm-3 |
| Bone: |
0.1 - 5 p.p.m. |
| Liver: |
20 - 70 p.p.m. |
| Muscle: |
20 - 70 p.p.m. |
| Daily dietary intake : |
1.5 - 6 mg |
| Total mass of element in average [70 kg] person: |
680 mg |
Crystal data
| Crystal structure, (cell dimentions / pm), space group |
b.c.c. (a = 562), Im3m |
| X-ray diffraction: mass absorption coefficients (µ/ρ)/cm2g-1 : |
CuKα 117 MoKα 90.0 |
| Neutron scattering length, b/10-12cm: |
0.709 |
| Thermal neutron capture cross-section, σa/barns : |
0.38 |
Geological data
| Minerals: |
No minerals as such are known, but rubidium is present in significant amounts in lepidolite (see lithium, pollucite (see caesium) and carnallite (see potassium). |
| World production: |
n.a. |
| Reserves: |
n.a. |
| Specimen: |
available as ingots in sealed ampoules. Danger! |
| Abundances |
|
| Sun: |
400 (relative to H = 1 x 1023) |
| Earth's crust: |
90 p.p.m. |
| Seawater: |
0.12 p.p.m. |
| Residence time: |
800 000 years |
| Classification: |
accumulating |
| Oxidation state: |
I |
Other sizes and specifications on request
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