Rubidium permanganate

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

Preparation
Rubidium permanganate can be formed by the reaction of potassium permanganate and rubidium chloride:


 * RbCl + KMnO4 -> KCl + RbMnO4 ↓

Physical
Rubidium permanganate is soluble in water with a solubility of 6.03 g/L at 7 °C, 10.6 g/L at 19 °C, and 46.8 g/L at 60 °C. Its crystal structure is orthorhombic, 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. The decomposition temperature is between 200 and 300 °C. Drift-away oxygen caused an 8% mass loss in the product.


 * 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.