Rubidium permanganate

Rubidium permanganate is the permanganate salt of rubidium, with the chemical formula RbMnO
4.

Rubidium permanganate
Identifiers
3D model (JSmol)
ChemSpider
  • InChI=1S/Mn.4O.Rb/q;;;;-1;+1
    Key: UJCOPKFKNRFWHO-UHFFFAOYSA-N
  • [Rb+].[O-][Mn](=O)(=O)=O
Properties
RbMnO4
Molar mass 204.404
Appearance purple crystals[1]
Density 3.325 g·cm−3[2]
Melting point 295 °C (decomposes)[2]
10.6 g·l−1 （19 °C）[3]
Structure
orthorhombic
Pnma (Nr. 62)
a = 954.11 pm, b = 573.926 pm, c = 763.63 pm
Related compounds
Other anions
 rubidium perchlorate
rubidium periodate
rubidium pertechnetate
Other cations
 lithium permanganate
sodium permanganate
potassium permanganate
ammonium permanganate
caesium permanganate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Preparation

Rubidium permanganate can be formed by the reaction of potassium permanganate and rubidium chloride:[4][5]

RbCl + KMnO4 → KCl + RbMnO4 ↓

Properties

Physical

Rubidium permanganate is soluble in water with a solubility of 6.03 g/L at 7 °C,[3] 10.6 g/L at 19 °C,[2] and 46.8 g/L at 60 °C.[6] Its crystal structure is orthorhombic,[1] the same as caesium permanganate, ammonium permanganate and potassium permanganate.

Chemical

Similar to potassium permanganate, the two-step decomposition of rubidium permanganate leads to the formation of rubidium manganate intermediates. It breaks down into manganese dioxide, rubidium oxide and oxygen.[4] The decomposition temperature is between 200 and 300 °C.[7] Drift-away oxygen caused an 8% mass loss in the product.[7]

10RbMnO4 → 3Rb2MnO4 + 7MnO2 + 2Rb2O + 6O2 ↑
2Rb2MnO4 → 2MnO2 + 2Rb2O + O2 ↑

Total reaction:

4RbMnO4 → 4MnO2 + 2Rb2O + 3O2 ↑

Uses

In qualitative analysis, rubidium permanganate is used as a reagent to detect perchlorate ions. It is produced as an intermediate from rubidium nitrate and potassium permanganate and precipitates with existing perchlorate ions as RbClO4·RbMnO4 mixed crystal.[8]

References
  1. R. Hoppe, D. Fischer, J. Schneider (1999), "Zur Kenntnis von Oxyden A[MO4]: Über LiMnO4, KMnO4, RbMnO4, CsMnO4 sowie RbIO4 und CsIO4. (– Was heißt eigentlich "Die Kristallstruktur von …"? –)", Zeitschrift für anorganische und allgemeine Chemie, vol. 625, no. 7, pp. 1521–3749, doi:10.1002/(SICI)1521-3749(199907)625:7<1135::AID-ZAAC1135>3.0.CO;2-L{{citation}}: CS1 maint: multiple names: authors list (link)
  2. Dale L. Perry, Sidney L. Phillips: Handbook of inorganic compounds. CRC Press, 1995, ISBN 978-0-8493-8671-8, S. 336 (, p. 336, at Google Books).
  3. Aterton Seidell (1940), [Volltext Solubilities of Organic Compounds], vol. 1, p. 1438 {{citation}}: Check |url= value (help)
  4. Michael W. Beck, Michael E. Brown (1983), "Thermal analysis of antimony/potassium permanganate pyrotechnic compositions" (PDF), Thermochimica Acta, vol. 65, no. 2–3, pp. 197–212, doi:10.1016/0040-6031(83)80022-7, archived from the original (PDF) on 2013-10-29
  5. P. J. Herley, E. G. Prout (1960), "The Thermal Decomposition of Rubidium Permanganate", The Journal of Physical Chemistry, vol. 64, no. 5, pp. 675–677, doi:10.1021/j100834a503
  6. Austin M. Patterson (1906), "Solubilities of Permanganates of the Alkali Metals", Journal of the American Chemical Society, vol. 28, no. 12, pp. 1734–1736, doi:10.1021/ja01978a009
  7. Z. Gontarz, B. Pisarska (September 1990), "Thermal decomposition stages of potassium, rubidium and caesium permanganates", Journal of Thermal Analysis and Calorimetry, vol. 36, no. 6, pp. 2113–2117, doi:10.1007/BF01914135, S2CID 95763664
  8. E. Gerdes (2001), [, p. 139, at Google Books Qualitative anorganische Analyse] (Ein Begleiter für Theorie und Praxis) (2 ed.), Springer, p. 139, ISBN 978-3-540-67875-5 {{citation}}: Check |url= value (help)
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