Rubidium compounds: rubidium iodide

rubidium symbol icon

The rubidium in rubidium iodide formally is in the oxidation state 1.

Crystal structure of rubidium iodide

Rubidium iodide

  • Formula as often written: RbI
  • Hill system formula: I1Rb1
  • CAS registry number: [7790-29-6]
  • Formula weight: 212.372
  • Class: iodide


  • rubidium iodide
  • rubidium(I) iodide

Physical properties

  • Colour: white
  • Appearance: crystalline solid
  • Melting point: 647°C; 642°C
  • Boiling point: 1300°C
  • Density: 3550 kg m-3


Coming soon...

Element analysis

Element percentages for the elements in rubidium iodide
Element %
I 59.76
Rb 40.24


One way to make rubidium iodide is to react the hydroxide with hydroiodic acid. The resulting salt can then be purified by recrystallization.

RbOH(aq) + HI(aq) → RbI(aq) + H2O(l)

Rubidium(I) iodide can also be made by the neutralization of rubidium(I) carbonate with hydroiodic acid. The resulting salt can then be purified by recrystallization.

Rb2(CO3)(aq) + 2HI(aq) → 2RbI(aq) + H2O(l) + CO2(g)

While not a normal route of preparation because of the expense, rubidium metal reacts vigorously with all the halogens to form rubidium halides. So, it burns with iodine, I2, to form rubidium(I) iodide, RbI.

2Rb(s) + I2(s) → 2RbI(s)

Solid state structure

  • Geometry of rubidium: 6 coordinate: octahedral
  • Prototypical structure: NaCl (rock salt)

Crystal structure of rubidium iodide

Isotope pattern

What follows is the calculated isotope pattern for the RbI unit with the most intense ion set to 100%.

Formula: Rb1I1

mass  %
212 100.0 __________________________________________________
213 0.0
214 38.6 ___________________


The data on these compounds pages are assembled and adapted from the primary literature and several other sources including the following.

  • R.T. Sanderson in Chemical Periodicity, Reinhold, New York, USA, 1960.
  • N.N. Greenwood and A. Earnshaw in Chemistry of the Elements, 2nd edition, Butterworth, UK, 1997.
  • F.A. Cotton, G. Wilkinson, C.A. Murillo, and M. Bochmann, in Advanced Inorganic Chemistry, John Wiley & Sons, 1999.
  • A.F. Trotman-Dickenson, (ed.) in Comprehensive Inorganic Chemistry, Pergamon, Oxford, UK, 1973.
  • R.W.G. Wyckoff, in Crystal Structures, volume 1, Interscience, John Wiley & Sons, 1963.
  • A.R.West in Basic solid state chemistry Chemistry, John Wiley & Sons, 1999.
  • A.F. Wells in Structural inorganic chemistry, 4th edition, Oxford, UK, 1975.
  • J.D.H. Donnay, (ed.) in Crystal data determinative tables, ACA monograph number 5, American Crystallographic Association, USA, 1963.
  • D.R. Lide, (ed.) in Chemical Rubber Company handbook of chemistry and physics, CRC Press, Boca Raton, Florida, USA, 77th edition, 1996.
  • J.W. Mellor in A comprehensive treatise on inorganic and theoretical chemistry, volumes 1-16, Longmans, London, UK, 1922-1937.
  • J.E. Macintyre (ed.) in Dictionary of inorganic compounds, volumes 1-3, Chapman & Hall, London, UK, 1992.

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rubidium atomic number