Rubidium

Rubidium, 37Rb
Rubidium
Pronunciation/ruːˈbɪdiəm/ (listenⓘ) ​(roo-BID-ee-əm)
Appearancegrey white
Standard atomic weight Ar°(Rb)
85.4678(3)
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
krypton ← rubidium → strontium
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 (near r.t.)1.532 g/cm3
when liquid (at m.p.)1.46 g/cm3
Triple point312.41 K, ​? kPa
Critical point2093 K, 16 MPa (extrapolated)
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 states−1, +1 (a strongly basic oxide)
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 structure ​body-centered cubic (bcc)
Body-centered cubic crystal structure for rubidium
Speed of sound thin rod1300 m/s (at 20 °C)
Thermal expansion90 µm/(m⋅K) (at r.t.)
Thermal conductivity58.2 W/(m⋅K)
Electrical resistivity128 nΩ⋅m (at 20 °C)
Magnetic orderingparamagnetic
Molar magnetic susceptibility+17.0×10−6 cm3/mol (303 K)
Young's modulus2.4 GPa
Bulk modulus2.5 GPa
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 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% 4.97×1010 y β− 87Sr
 Category: Rubidium
| references
Rubidium in a glass tube

Rubidium is chemical element 37 on the periodic table. Its symbol is Rb. Its atomic mass is 85.47. It has 37 protons and 37 electrons. It is a soft silver colored metal. It was first discovered in 1861 by Robert Bunsen and Gustav Kirchoff in Heidelberg, Germany.

Properties

Physical properties

Rubidium melts at a very low temperature, for example it could melt in a person's hand. Rubidium is an alkali metal. It can make an amalgam with mercury.

Chemical properties

Rubidium is very reactive. It will ignite in air because it reacts with many other elements in the air like oxygen and nitrogen. Rubidium reacts very violently with water to make hydrogen and rubidium hydroxide, a strong corrosive base. The reaction is normally very hot so the hydrogen ignites.

Chemical compounds

Rubidium chloride

Rubidium forms chemical compounds in only one oxidation state: +1. Some rubidium compounds have a mixed oxidation state, though. Rubidium chloride is the most common rubidium compound. Rubidium hydroxide and rubidium carbonate are also used commonly. Rubidium compounds makes a red-violet color in a flame. Most rubidium compounds are colorless. Rubidium compounds are not as common as other alkali metal compounds, such get sodium compounds. Otherwise, they are similar.

Occurrence and preparation

Rubidium is about as common as zinc. It is the 23rd most common element in the Earth's crust. Most minerals only have a small amount of rubidium in them. It normally comes in small quantities in other minerals. It is made by reduction of rubidium ores with calcium. It is expensive because calcium is difficult to make and the rubidium needs to be kept in argon and away from water or air.

Uses

There are not many common uses for rubidium. Rubidium compounds are sometimes used in purple fireworks. It and its compounds are used mainly in science research though. It is also used to make superoxide ions. It is used in some special types of glass.

Safety

Rubidium compounds are not very dangerous in the human body; however, if a person gets too much from eating, they could get sick because it acts like other alkali metal ions such as sodium ions in sodium chloride. Rats can live with up to half of their potassium replaced with rubidium, though it is not likely for that to happen.

Rubidium metal is very dangerous. It reacts with air and water and makes the corrosive substance rubidium hydroxide.

References

  1. ↑ "Standard Atomic Weights: Rubidium". CIAAW. 1969.
  2. 1 2 Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, FL: CRC Press. p. 4.122. ISBN 1439855110.
  3. ↑ Cverna, Fran (2002). "Ch. 2 Thermal Expansion". ASM Ready Reference: Thermal properties of metals (PDF). ASM International. ISBN 978-0-87170-768-0.
  4. ↑ 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.
  5. ↑ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
  6. ↑ 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.
  7. 1 2 3 "Visual Elements: Rubidium". rsc.org. 2011. Retrieved 26 June 2011.