What is Rubidium?

PrintPrintEmailEmailSaveSave
Image Credit: 
wiki.chemeddl.org
Main Image: 
Rubidium.

Rubidium is a metallic element sited in the alkaline group on the periodic table of elements. It is used in a variety of industries, and it is also utilized in laboratories for a range of experiments. The element also has a number of radioactive isotopes which are used in research and dating of ancient fossils. Rubidium is highly reactive, making it somewhat difficult to handle since it can be unstable in oxygen rich environments. We interact with rubidium in the form of a component in a variety of household goods. Rubidium metal is easily vaporized and has a convenient spectral absorption range, making it a frequent target for laser manipulation of atoms. Its compounds have chemical and electronic applications. Rubidium is not known to be necessary for any living organisms. However, like caesium, rubidium ions are handled by living organisms in a manner similar to potassium ions: they are actively taken up by plants and living animal You do not have access to view this node.

 

Rubidium is the twenty-third most abundant element in the Earth's crust, roughly as abundant as zinc and rather more common than copper. Due to its large ionic radius, rubidium is one of the "incompatible elements”. An incompatible element is an element that is unsuitable in size and/or charge. During magma crystallization, rubidium is concentrated together with its heavier analogue cesium in the liquid phase and crystallizes last. Crystallization is one of the most important geochemical and physical processes operating within the Earth's crust. Therefore the largest deposits of rubidium and caesium are zone pegmatite ore bodies formed by this enrichment process. A pegmatite is a very coarse-grained, intrusive igneous rock composed of interlocking grains usually larger than 2.5 cm in size.

 

What is the History of Rubidium?

German chemists Robert Bunsen and Gustav Kirchhoff discovered rubidium in 1861 by the newly developed method of flame spectroscopy. Due to the bright red lines in its emission spectrum, they chose a name derived from the Latin word “rubidus”, meaning “dark red”. Rubidium was the second element, shortly after caesium, to be discovered spectroscopically, only one year after the invention of the spectroscope by Bunsen and Kirchhoff. They tried to generate elemental rubidium by electrolysis of molten rubidium chloride, but instead of a metal, they obtained a blue homogenous substance which "neither under the naked eye nor under the microscope showed the slightest trace of metallic substance”.

 

Rubidium had minimal industrial value before the 1920s. Since then, the most important use of rubidium has been in research and development, primarily in chemical and electronic applications. In 1995, rubidium-87, the rubidium isotope was used to produce a Bose-Einstein condensate (is a state of matter of a dilute gas of weakly interacting bosons, the sub-atomic particles confined in an external potential and cooled to temperatures very near absolute zero) for which the discoverers won the 2001 Nobel Prize in Physics.

 

What are the properties of Rubidium?

  • Rubidium is a chemical element with the symbol Rb and atomic number 37.
  • Rubidium is a soft, silvery-white metallic element of the alkali metal group.
  • Its atomic mass is 85.4678.
  • Elemental rubidium is highly reactive, with properties similar to those of other elements in group 1 in the periodic table, such as very rapid oxidation in air.
  • Rubidium has only one stable isotope, Rb-85. The isotope Rb-87, which composes almost 28% of naturally occurring rubidium, is radioactive and has a half-life of 49 billion years—more than three times longer than the estimated age of the universe.
  • The Boiling Point of Rubidium is 961 Kelvin.
  • It melts at 39.3 degree C.
  • Rubidium has very low ionization energy of only 406 J/mol.
  • Rubidium and potassium shows a very similar violet color in the flame test which makes spectroscopy methods necessary to distinguish the two elements.

 

What are the isotopes of Rubidium?

  • Naturally occurring rubidium is composed of two isotopes: the stable Rb-85 (72.2%) and the radioactive Rb-87 (27.8%).
  • Natural rubidium is radioactive with enough to significantly expose a photographic film in 110 days.
  • Apart from Rb-85 and Rb-87, another 24 isotopes are known with half times of under 3 months. Most of them are highly radioactive and have little uses.
  • Rubidium-87 has a half-life of 4.88×1010 years, which is more than three times the age of the universe.
  • It readily substitutes for potassium in minerals, and is therefore fairly widespread. Rb has been used extensively in dating rocks (is a technique used to date materials such as rocks).

 

What are the applications of Rubidium?

  • Rubidium compounds are sometimes used in fireworks to give them a purple color. Rubidium has also been considered for use in a thermoelectric generator.
  • These conduct electricity and act like an armature (one of the two principal electrical components of an electromechanical machine) of a generator thereby generating an electric current.
  • Rubidium, particularly vaporized 87Rb, is one of the most commonly used atomic species employed for laser cooling. Laser cooling refers to the number of techniques in which atomic and molecular samples are cooled through the interaction with one or more laser light fields.
  • Other potential or current uses of rubidium include a working fluid in vapor turbines, a getter in vacuum tubes and a photocell component. A getter is a deposit of reactive material that is deliberately placed inside a vacuum system.
  • Rubidium collects more in brain tumors than normal brain tissue, allowing to use the radioisotope rubidium-82 in nuclear medicine to locate and image brain tumors.
  • Rubidium is also used in the production of glass and ceramic and it can also be found in electron tubes, atomic clocks.

 

What are the Health and Environmental effects of Rubidium?

  • Exposure to rubidium causes chemical burns of eyes and You do not have access to view this node.
  • Rubidium reacts violently with water and can cause fires.
  • Rubidium has no known biological role but has a slight stimulatory effect on metabolism, probably because it is like potassium. The two elements are found together in minerals and soils.
  • Plant will adsorb rubidium quite quickly. When stresses by deficiency of potassium some plants, such as sugar beet, will respond to the addition of rubidium. In this way rubidium enters the food chain and so contributes to a daily intake of between 1 and 5 mg.
  • No negative environmental effects have been reported.

 

External References
Related Videos: 
See video