{"id":29,"date":"2020-04-08T14:57:02","date_gmt":"2020-04-08T14:57:02","guid":{"rendered":"https:\/\/thechemicalelements.com\/?page_id=29"},"modified":"2023-08-16T11:00:51","modified_gmt":"2023-08-16T11:00:51","slug":"rubidium","status":"publish","type":"post","link":"https:\/\/thechemicalelements.com\/rubidium\/","title":{"rendered":"Rubidium (Rb)"},"content":{"rendered":"\n

Rubidium is a chemical element with the atomic number 37 in the periodic table. With an occurrence of 90 parts per million by weight, it\u2019s the 25th most abundant chemical element found in Earth\u2019s crust. As a member of the alkali group of metals<\/a>, this soft, silvery-white chemical has one valence electron positioned in the s-orbital of the atom’s fifth energy level.\u00a0<\/span><\/p>\n\n\n\n

Despite its natural plentifulness, rubidium extraction and processing require some of the most difficult and expensive processes, which limits the everyday use of this chemical element immensely.\u00a0<\/span><\/p>\n\n\n\n

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Chemical and Physical Properties of Rubidium<\/span><\/h3>\n\n\n\n
Property<\/strong><\/td>Value<\/strong><\/td><\/tr>
Symbol<\/td>Rb<\/td><\/tr>
Name<\/td>Rubidium<\/td><\/tr>
Atomic number<\/td>37<\/td><\/tr>
Atomic weight (mass)<\/td>85.4678 g.mol-1<\/td><\/tr>
Uses<\/td>Used as a catalyst, photocells, and vacuum and cathode-ray tubes.<\/td><\/tr>
Description<\/td>Soft, malleable, silvery-yellow metal.<\/td><\/tr>
Group<\/td>Alkali Metal<\/a><\/td><\/tr>
Shells<\/td>2,8,18,8,1<\/td><\/tr>
Valence<\/td>1,2,3,4<\/td><\/tr>
Crystal Structure<\/td>Cubic: Body centered<\/td><\/tr>
Electronegativity<\/td>0.82<\/td><\/tr>
Covalent Radius<\/td>2.16 \u00c5<\/td><\/tr>
Atomic Radius<\/td>2.98 \u00c5<\/td><\/tr>
Atomic Volume<\/td>55.9 cm\u00b3\/mol<\/td><\/tr>
Name Origin<\/td>Latin: rubidus (deep red); the color its salts impart to flames.<\/td><\/tr>
Discovered By<\/td>R. Bunsen, G. Kirchoff<\/td><\/tr>
Year<\/td>1861<\/td><\/tr>
Location<\/td>Germany<\/td><\/tr>
Pronunciation<\/td>roo-BID-i-em<\/td><\/tr>
Oxydation States<\/td>1<\/td><\/tr>
Color<\/td>A silvery-white metallic element<\/td><\/tr>
Physical state<\/td>Solid at room temperature<\/td><\/tr>
Half-life<\/td>From less than 1.5 microseconds to 4.923(22)\u00d71010 years<\/td><\/tr>
Density<\/td>1.53 g.cm-3 at 20\u00b0C<\/td><\/tr>
Melting point<\/td>39.30\u00b0C, 102.74\u00b0F, 312.45 K<\/td><\/tr>
Boiling point<\/td>688\u00b0C, 1270\u00b0F, 961 K<\/td><\/tr>
Van der Waals radius<\/td>0.243 nm<\/td><\/tr>
Ionic radius<\/td>1.61 (+1) \u00c5<\/td><\/tr>
Isotopes<\/td>36<\/td><\/tr>
Most characteristic isotope<\/td>85Rb, 87Rb<\/td><\/tr>
Electronic shell<\/td>[Kr] 5s1<\/td><\/tr>
The energy of the first ionization<\/td>402.9 kJ.mol-1<\/td><\/tr>
The energy of the second ionization<\/td>2633 kJ.mol-1<\/td><\/tr>
The energy of the third ionization<\/td>3860 kJ.mol-1<\/td><\/tr>
Discovery date<\/td>In 1861 by Gustav Kirchhoff and Robert Bunsen<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
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With the periodic table symbol Rb, atomic number 37, atomic mass of 85.4678 g.mol-1, and electron configuration [Kr] 5s1, rubidium is a soft, silvery-white metal composed of two isotopes. It reaches its boiling point at 688\u00b0C, 1270\u00b0F, 961 K, while the melting point is achieved at 39.30\u00b0C, 102.74\u00b0F, 312.45 K. This member of the alkali metals family of elements in the periodic table has an electronegativity of 0.8 according to Pauling, whereas the atomic radius according to van der Waals is 0.243 nm.\u00a0<\/span><\/p>\n\n\n\n

Rubidium metal is the second most electropositive of the stable alkali metals. Like the other alkali metals (lithium<\/a>, sodium, potassium<\/a>, cesium, and francium<\/a>), this chemical is highly reactive with both air and water. When exposed to air, rubidium spontaneously ignites, while with H2O it creates an equally volatile reaction.\u00a0<\/span><\/p>\n\n\n\n

As with the other alkalis, the water reaction with rubidium produces hydrogen<\/a> gas and is vigorous enough to ignite the liberated hydrogen. Rubidium oxidizes in contact with air; due to this, rubidium must be kept either under dry mineral oil or in a vacuum or inert atmosphere.<\/span><\/p>\n\n\n\n

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How Was Rubidium Discovered?<\/span><\/h2>\n\n\n\n

In 1861, the German chemists Robert Bunsen and Gustav Kirchhoff dedicated their scientific interest to the analysis of the mineral lepidolite. In their Heidelberg laboratory, they were trying to employ the spectroscope (which they co-discovered only a year earlier) in the analysis of a lepidolite sample. The mineral that captured the scientific curiosity of Bunsen and Kirchhoff was obtained from Saxony, Germany.<\/span><\/p>\n\n\n\n

In the first step of their scientific trial, the scientists used hydrochloroplatinic acid to precipitate potassium chloroplatinate from the mineral. This method produced yet another type of salt. This time, they used the <\/span>Bunsen burner<\/span><\/i>. In this way, the discoverers of rubidium observed a spectrum rich in new lines, among which two were strikingly clear and inclined to the red solar spectrum.\u00a0<\/span><\/p>\n\n\n\n

By using the method of electrolysis, Bunsen also managed to isolate the first sample of pure rubidium metal and determine a larger portion of its chemical properties.<\/span><\/p>\n\n\n\n

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How Did Rubidium Get Its Name?<\/span><\/h2>\n\n\n\n

The name of element 37 originates from the Latin word ‘<\/span>rubidus<\/span><\/i>‘, which means \u2018<\/span>deepest red<\/span><\/i>\u2019. This term refers to the deep red lines displayed by rubidium in the spectrum, by which its discoverers Bunsen and Kirchhoff succeeded to detect the new element.\u00a0<\/span><\/p>\n\n\n\n

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Where Can You Find Rubidium?<\/span><\/h2>\n\n\n\n

Naturally, this chemical element occurs in igneous rocks, shale, sandstone, freshwater, marine and land plants, soil, and both land and marine animals. Furthermore, rubidium can be found in many minerals, such as zinnwaldite, carnallite, pollucite, leucite, and lepidolite. Potassium chlorides, potassium minerals, and brines also contain some rubidium quantities.\u00a0<\/span><\/p>\n\n\n\n

The mines richest in rubidium are found on the island of Elba and in Manitoba, Canada. Element 37 is typically isolated as a byproduct of lithium extraction for commercial purposes. In cases where rubidium metal occurs along with other alkalis such as cesium, this chemical is extracted by an ion-exchange method, chemical reduction with sodium or calcium<\/a>, or by the use of electrolysis.<\/span><\/p>\n\n\n\n

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Rubidium in Everyday Life<\/span><\/h2>\n\n\n\n

Despite being one of the most abundant elements in Earth\u2019s crust, rubidium is a substance that is hard to extract and process. The complex extraction and the limited supply of this chemical add to its high price while limiting its everyday use:<\/span><\/p>\n\n\n\n