Chemical element with atomic number 37 (Rb)
Rubidium, 37 Rb Pronunciation (roo-BID -ee-əm ) Appearance grey white
Atomic number (Z ) 37 Group group 1: hydrogen and alkali metals Period period 5 Block s-block Electron configuration [Kr ] 5s1 Electrons per shell 2, 8, 18, 8, 1 Phase at STP solid Melting point 312.45 K (39.30 °C, 102.74 °F) Boiling point 961 K (688 °C, 1270 °F) Density (at 20° C) 1.534 g/cm3 [ 3] when liquid (at m.p. ) 1.46 g/cm3 Triple point 312.41 K, ? kPa[ 4] Critical point 2093 K, 16 MPa (extrapolated) [ 4] Heat of fusion 2.19 kJ/mol Heat of vaporization 69 kJ/mol Molar heat capacity 31.060 J/(mol·K) Vapor pressure
P (Pa)
1
10
100
1 k
10 k
100 k
at T (K)
434
486
552
641
769
958
Oxidation states −1, +1 (a strongly basic oxide) Electronegativity Pauling scale: 0.82 Ionization energies 1st: 403 kJ/mol 2nd: 2632.1 kJ/mol 3rd: 3859.4 kJ/mol Atomic radius empirical: 248 pm Covalent radius 220±9 pm Van der Waals radius 303 pm Spectral lines of rubidiumNatural occurrence primordial Crystal structure body-centered cubic (bcc) (cI2 ) Lattice constant a = 569.9 pm (at 20 °C)[ 3] Thermal expansion 85.6× 10−6 /K (at 20 °C)[ 3] Thermal conductivity 58.2 W/(m⋅K) Electrical resistivity 128 nΩ⋅m (at 20 °C) Magnetic ordering paramagnetic [ 5] Molar magnetic susceptibility +17.0× 10−6 cm3 /mol (303 K)[ 6] Young's modulus 2.4 GPa Bulk modulus 2.5 GPa Speed of sound thin rod 1300 m/s (at 20 °C) Mohs hardness 0.3 Brinell hardness 0.216 MPa CAS Number 7440-17-7 Discovery Robert Bunsen and Gustav Kirchhoff (1861) First isolation George de Hevesy
Category: Rubidium | references
Rubidium is a chemical element ; it has symbol Rb and atomic number 37. It is a very soft, whitish-grey solid in the alkali metal group, similar to potassium and caesium .[ 8] Rubidium is the first alkali metal in the group to have a density higher than water . On Earth, natural rubidium comprises two isotopes : 72% is a stable isotope 85 Rb, and 28% is slightly radioactive 87 Rb, with a half-life of 48.8 billion years—more than three times as long as the estimated age of the universe .
German chemists Robert Bunsen and Gustav Kirchhoff discovered rubidium in 1861 by the newly developed technique, flame spectroscopy . The name comes from the Latin word rubidus , meaning deep red, the color of its emission spectrum. Rubidium's compounds have various chemical and electronic applications. Rubidium metal is easily vaporized and has a convenient spectral absorption range, making it a frequent target for laser manipulation of atoms .[ 9] Rubidium is not a known nutrient for any living organisms . However, rubidium ions have similar properties and the same charge as potassium ions, and are actively taken up and treated by animal cells in similar ways.
^ "Standard Atomic Weights: Rubidium" . CIAAW . 1969.
^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)" . Pure and Applied Chemistry . doi :10.1515/pac-2019-0603 . ISSN 1365-3075 .
^ a b c Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements . Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9 .
^ a b Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, FL: CRC Press . p. 4.122. ISBN 1-4398-5511-0 .
^ Lide, D. R., ed. (2005). "Magnetic susceptibility of the elements and inorganic compounds". CRC Handbook of Chemistry and Physics (PDF) (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5 .
^ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics . Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4 .
^ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF) . Chinese Physics C . 45 (3): 030001. doi :10.1088/1674-1137/abddae .
^ Lenk, Winfried; Prinz, Horst; Steinmetz, Anja (2010). "Rubidium and Rubidium Compounds". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi :10.1002/14356007.a23_473.pub2 . ISBN 978-3527306732 .
^ "Rubidium (Rb) | AMERICAN ELEMENTS ®" . American Elements: The Materials Science Company . Retrieved 2024-03-27 .