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|Atomic Number:||37||Atomic Symbol:||Rb|
|Atomic Weight:||85.4678||Electron Configuration:||2-8-18-8-1|
|Melting Point:||39.4oC||Boiling Point:||688oC|
|Uses:||For heart muscle research, semiconductors, wide-angle lenses|
History(L. rubidus, deepest red) Discovered in 1861 by Bunsen and
Kirchoff in the mineral lepidolite by use of the spectroscope.
SourcesThe element is much more abundant than was thought several years
It is now considered to be the 16th most abundant element in the earth's
Rubidium occurs in pollucite, leucite, and zinnwaldite, which contains
traces up to 1%, in the form of the oxide.
It is found in lepidolite to the
extent of about 1.5%, and is recovered commercially from this
Potassium minerals, such as those found at Searles Lake, California,
and potassium chloride recovered from the brines in Michigan also contain the
element and are commercial sources.
It is also found along with cesium in the
extensive deposits of pollucite at Bernic Lake, Manitoba.
- Rubidium can be liquid at room temperature.
- It is a soft, silvery-white metallic element of the alkali group and is the
second most electropositive and alkaline element.
- It ignites spontaneously in air and reacts violently in water, setting fire
to the liberated hydrogen.
- As with other alkali metals, it forms amalgams with mercury and it alloys
with gold, cesium, sodium, and potassium.
- It colors a glame yellowish violet.
- Rubidium metal can be prepared by reducing rubidium chloride with calcium,
and by a number of other methods.
- It must be kept under a dry mineral oil or in a vacuum or inert atmosphere.
- Twenty four isotopes of rubidium are known.
- Naturally occuring rubidium is made of two isotopes, 85Rb and 87Rb.
- Rubidium-87 is present to the extent of 27.85% in natural rubidium and is a
beta emitter with a half-life of 4.9 x 1010
- Ordinary rubidium is sufficiently radioactive to expose a photographic film
in about 30 to 60 days.
CompoundsRubidium forms four oxides: Rb2O, Rb2O2, Rb2O3, Rb2O4.
UsesBecause rubidium can be easily ionized, it has been considered for use in
"ion engines" for space vehicles; however, cesium is somewhat more efficient for
It is also proposed for use as a working fluid for vapor turbines and for
use in a thermoelectric generator using the magnetohydrodynamic principle where
rubidium ions are formed by heat at high temperature and passed through a
These conduct electricity and act like an amature of a generator thereby
generating an electric current.
Rubidium is used as a getter in vacuum tubes and as a photocell
It has been used in making special glasses.
important, as it has the highest room conductivity of any known ionic
At 20C its conductivity is about the same as dilute sulfuric acid.
This suggests use in thin film batteries and other applications.
CostThe present cost in small quantities is about $25/g.