Rubidium, 37Rb
Rubidium
Pronunciation/rˈbɪdiəm/ (roo-BID-ee-əm)
Appearancegrey white
Standard atomic weight Ar°(Rb)
Rubidium in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
K

Rb

Cs
kryptonrubidiumstrontium
Atomic number (Z)37
Groupgroup 1: hydrogen and alkali metals
Periodperiod 5
Block  s-block
Electron configuration[Kr] 5s1
Electrons per shell2, 8, 18, 8, 1
Physical properties
Phase at STPsolid
Melting point312.45 K ​(39.30 °C, ​102.74 °F)
Boiling point961 K ​(688 °C, ​1270 °F)
Density (at 20° C)1.534 g/cm3[3]
when liquid (at m.p.)1.46 g/cm3
Triple point312.41 K, ​? kPa[4]
Critical point2093 K, 16 MPa (extrapolated)[4]
Heat of fusion2.19 kJ/mol
Heat of vaporization69 kJ/mol
Molar heat capacity31.060 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
Atomic properties
Oxidation statescommon: +1
−1?
ElectronegativityPauling scale: 0.82
Ionization energies
  • 1st: 403 kJ/mol
  • 2nd: 2632.1 kJ/mol
  • 3rd: 3859.4 kJ/mol
Atomic radiusempirical: 248 pm
Covalent radius220±9 pm
Van der Waals radius303 pm
Color lines in a spectral range
Spectral lines of rubidium
Other properties
Natural occurrenceprimordial
Crystal structurebody-centered cubic (bcc) (cI2)
Lattice constant
Body-centered cubic crystal structure for rubidium
a = 569.9 pm (at 20 °C)[3]
Thermal expansion85.6×10−6/K (at 20 °C)[3]
Thermal conductivity58.2 W/(m⋅K)
Electrical resistivity128 nΩ⋅m (at 20 °C)
Magnetic orderingparamagnetic[5]
Molar magnetic susceptibility+17.0×10−6 cm3/mol (303 K)[6]
Young's modulus2.4 GPa
Bulk modulus2.5 GPa
Speed of sound thin rod1300 m/s (at 20 °C)
Mohs hardness0.3
Brinell hardness0.216 MPa
CAS Number7440-17-7
History
DiscoveryRobert Bunsen and Gustav Kirchhoff (1861)
First isolationGeorge de Hevesy
Isotopes of rubidium
Main isotopes[7] Decay
abun­dance half-life (t1/2) mode pro­duct
82Rb synth 1.2575 m β+ 82Kr
83Rb synth 86.2 d ε 83Kr
γ
84Rb synth 32.9 d ε 84Kr
β+ 84Kr
γ
β 84Sr
85Rb 72.2% stable
86Rb synth 18.7 d β 86Sr
γ
87Rb 27.8% 4.923×1010 y β 87Sr
 Category: Rubidium
| references
Rb · Rubidium
Kr ←

ibox Kr

iso
37
Rb  [e]
IB-Rb [e]
IBisos [e]
→ Sr

ibox Sr

indexes by PT (page)
child table, as reused in {IB-Rb}
Main isotopes of rubidium
Main isotopes[7] Decay
abun­dance half-life (t1/2) mode pro­duct
82Rb synth 1.2575 m β+ 82Kr
83Rb synth 86.2 d ε 83Kr
γ
84Rb synth 32.9 d ε 84Kr
β+ 84Kr
γ
β 84Sr
85Rb 72.2% stable
86Rb synth 18.7 d β 86Sr
γ
87Rb 27.8% 4.923×1010 y β 87Sr
Data sets read by {{Infobox element}}
Name and identifiers
Symbol etymology (11 non-trivial)
Top image (caption, alt)
Pronunciation
Allotropes (overview)
Group (overview)
Period (overview)
Block (overview)
Natural occurrence
Phase at STP
Oxidation states
Spectral lines image
Electron configuration (cmt, ref)
Isotopes
Standard atomic weight
  most stable isotope
Wikidata
Wikidata *
* Not used in {{Infobox element}} (2023-01-01)
See also {{Index of data sets}} · Cat:data sets (46) · (this table: )

References

  1. ^ "Standard Atomic Weights: Rubidium". CIAAW. 1969.
  2. ^ 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.
  3. ^ 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.
  4. ^ 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.
  5. ^ 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.
  6. ^ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
  7. ^ a b 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.