Rubidium Elemental Symbol (Rb)

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Rubidium Rubidium Rubidio Rubídio Rubidio Rubidium

Rubidium(Rb) atomic and molecular weight, atomic number and elemental symbolRubidium is a Block S, Group 1, Period 5 element. Rubidium Bohr ModelThe number of electrons in each of Rubidium's shells is 2, 8, 18, 8, 1 and its electronic configuration is [Kr] 5s1. The rubidium atom has a radius of and a Van der Waals radius of Rubidium is highly reactive, with properties similar to other Group 1 elements, e.g., rapid oxidation in air. In its elemental form, CAS 7440-17-7, rubidium has a gray white appearance. Rubidium is found in the minerals lepidolite, leucite, pollucite, carnallite, and zinnwaldite as well as some potassium minerals. Rubidium was first discovered by Robert Bunsen and Gustav Kirchhoff in 1861. The name Rubidium, originates from the Latin word rubidus, which means dark or deepest red.

Rubidium has various applications in medicine and photo-electronics. High Purity (99.999%) Rubidium Oxide (Rb2O) Powder Since it is easily vaporized, rubidium's spectral absorption range is a good target for laser manipulation of atoms. Rubidium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). Elemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. Nanoparticles and nanopowders provide ultra-high surface area which nanotechnology research and recent experiments demonstrate function to create new and unique properties and benefits. Oxides are available in forms including powders and dense pellets for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Rubidium is available in soluble forms including chlorides, nitrates and acetates. These compounds are also manufactured as solutions at specified stoichiometries.

Safety data for rubidium compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab below.

  • Properties
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  • Research
  • Isotopes
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Rubidium Properties

Symbol: Rb Melting Point: 312.46 K, 39.31 °C, 102.76 °F
Atomic Number: 37 Boiling Point: 961 K, 688 °C, 1270 °F
Atomic Weight: 85.4678 Density: 1.532 g·cm−3
Element Category: alkali metal Liquid Density @ Melting Point: 1.46 g·cm−3
Group, Period, Block: 1, 5, s Specific Heat: 0.363J/gK
    Heat of Vaporization 75.7 kJ mol-1
CHEMICAL STRUCTURE Heat of Fusion 2.2 kJ mol-1
Electrons: 37 Thermal Conductivity: 58.2 W·m−1·K−1
Protons: 37 Thermal Expansion: N/A
Neutrons: 48 Electrical Resistivity: (20 °C) 128 nΩ·m
Electron Configuration: [Kr] 5s1 2, 8, 18, 8, 1 Electronegativity: 0.82 (Pauling scale)
Atomic Radius: 248 pm Tensile Strength: N/A
Covalent Radius: 220±9 pm Molar Heat Capacity: 31.060 J·mol−1·K−1
Van der Waals radius: 303 pm Young's Modulus: 2.4 GPa
Oxidation States: 1 (strongly basic oxide) Shear Modulus: N/A
Phase: Solid Bulk Modulus: 2.5 GPa
Crystal Structure: body-centered cubic Poisson Ratio: N/A
Magnetic Ordering: paramagnetic Mohs Hardness: 0.3
1st Ionization Energy: 403.03 kJ mol-1 Vickers Hardness: N/A
2nd Ionization Energy: 2632.62 kJ mol-1 Brinell Hardness: 0.216 MPa
3rd Ionization Energy: 3859.44 kJ mol-1 Speed of Sound: (20 °C) 1300 m·s−1
CAS Number: 7440-17-7 Abundance in typical human body, by weight: 4600 ppb
ChemSpider ID: 4512975 Abundance in typical human body, by atom: 340 ppb
PubChem CID: 5357696 Abundance in universe, by weight: 10 ppb
MDL Number: MFCD00134055 Abundance in universe, by atom: 0.1 ppb
EC Number: 231-126-6 Discovered By: Robert Bunsen and Gustav Kirchhoff
Beilstein Number: N/A Discovery Date: 1861
SMILES Identifier: [Rb]  
InChI Identifier: InChI=1S/Rb Other Names: Rubidij, Rubidio

Recent Research & Development for Rubidium

  • Eun Hyun Cha, Taek Jeong, Heung-Ryoul Noh, Two-color polarization spectroscopy in V-type configuration in rubidium, Optics Communications, Volume 326, 1 September 2014
  • Radoslaw Chrapkiewicz, Wojciech Wasilewski, Czeslaw Radzewicz, How to measure diffusional decoherence in multimode rubidium vapor memories?, Optics Communications, Volume 317, 15 April 2014
  • Anqing Jiao, Hongping Wu, Shilie Pan, Hongwei Yu, Zhihua Yang, Chen Lei, Synthesis, structure, and characterization of a new rubidium cadmium borate: RbCdB3O6, Journal of Alloys and Compounds, Volume 588, 5 March 2014
  • R. Král, K. Nitsch, V. Babin, J. Šulc, H. Jelínková, Y. Yokota, A. Yoshikawa, M. Nikl, Growth and optical properties of RE-doped ternary rubidium lead chloride single crystals, Optical Materials, Volume 36, Issue 2, December 2013
  • A.V. Anikeenko, N.N. Medvedev, N.F. Uvarov, Molecular dynamics study of ion migration mechanism in rubidium nitrate, Solid State Ionics, Volume 251, 15 November 2013
  • Pawel Krys, Flaviano Testa, Andrzej Trochimczuk, Christian Pin, Jean-Marie Taulemesse, Thierry Vincent, Eric Guibal, Encapsulation of ammonium molybdophosphate and zirconium phosphate in alginate matrix for the sorption of rubidium(I), Journal of Colloid and Interface Science, Volume 409, 1 November 2013
  • Hichri Monia, Zamali Hmida, Khattech Ismail, Heat capacities and enthalpies of fusion of lithium and rubidium nitrates: Heat capacities, enthalpies of fusion and enthalpies of formation of the intermediate compounds Ag0.5Rb0.5NO3 and Li0.5Rb0.5NO3, Thermochimica Acta, Volume 568, 20 September 2013
  • Brian K. Nicholson, Christopher J. Clark, Geoffrey B. Jameson, Shane G. Telfer, Rubidium-templated bowl-shaped isopolyoxoantimonates [RbH11-x(RSb)14O34]x- derived from arylstibonic acids, Inorganica Chimica Acta, Volume 406, 1 September 2013
  • Aiqin Mao, Hua Wang, Renming Pan, Corrigendum to “Coke deactivation of activated carbon-supported rubidium-potassium catalyst for C2F5I gas-phase synthesis” [J. Fluorine Chem. 150 (2013) 21–24], Journal of Fluorine Chemistry, Volume 153, September 2013
  • Aiqin Mao, Hua Wang, Renming Pan, Coke deactivation of activated carbon-supported rubidium–potassium catalyst for C2F5I gas-phase synthesis, Journal of Fluorine Chemistry, Volume 150, June 2013
  • Taek Jeong, Jun Yeon Won, Heung-Ryoul Noh, Line shapes in polarization spectroscopy for the rubidium D1 line in an external magnetic field, Optics Communications, Volume 292, 1 April 2013
  • N. Korneev, Y.M. Torres, Pattern-based optical memory with low power switching in rubidium vapor, Optics Communications, Volume 291, 15 March 2013
  • Lindsay O’Brien Quarrie, The effects of atomic rubidium vapor on the performance of optical windows in Diode Pumped Alkali Lasers (DPALs), Optical Materials, Volume 35, Issue 5, March 2013
  • Berceste Beyribey, Jonathan Hallinder, Finn Willy Poulsen, Nikolaos Bonanos, Mogens Mogensen, Studies of rubidium selenate with secondary phase of RbOH under humidified reducing atmosphere, Journal of Alloys and Compounds, Volume 545, 25 December 2012
  • M. Igarashi, T. Nakano, A. Goto, K. Hashi, T. Shimizu, A. Hanazawa, Y. Nozue, NMR property of rubidium loaded sodalite, Journal of Physics and Chemistry of Solids, Volume 73, Issue 12, December 2012
  • Min Jeong Seo, Heung-Ryoul Noh, Self-rotation of elliptically polarized light in Doppler-broadened rubidium atoms, Optics Communications, Volume 285, Issue 24, 1 November 2012
  • Berceste Beyribey, Jonathan Hallinder, Structural, thermal and electrical studies of a novel rubidium phosphite tellurate compound, Ceramics International, Volume 38, Issue 6, August 2012
  • P. Kulatunga, H.C. Busch, L.R. Andrews, C.I. Sukenik, Two-color polarization spectroscopy of rubidium, Optics Communications, Volume 285, Issue 12, 1 June 2012
  • Si-Cong Tian, Zhi-Hui Kang, Chun-Liang Wang, Ren-Gang Wan, Jun Kou, Hang Zhang, Yun Jiang, Hai-Ning Cui, Jin-Yue Gao, Observation of spontaneously generated coherence on absorption in rubidium atomic beam, Optics Communications, Volume 285, Issue 3, 1 February 2012
  • N.M. Laptash, A.A. Udovenko, T.B. Emelina, Dynamic orientation disorder in rubidium fluorotantalate. Synchronous Ta–O and Ta–F vibrations, Journal of Fluorine Chemistry, Volume 132, Issue 12, December 2011

Rubidium Isotopes

Rubidium (Rb) has 32 isotopes, two of which are naturally occurring: 85Rb (72.2%) and the radioactive 87Rb (27.8%).

Nuclide Symbol Isotopic Mass Half-Life Nuclear Spin
85Rb 84.911789738 Stable 5/2-
87Rb 86.909180527 4.923(22)×1010 a 3/2-