Rubidium permanganate

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

Rubidium permanganate

Identifiers
CAS Number	13465-49-1
3D model (JSmol)	Interactive image
ChemSpider	13389592
PubChem CID	23674440
CompTox Dashboard (EPA)	DTXSID00635477
InChI InChI=1S/Mn.4O.Rb/q;;;;-1;+1 Key: UJCOPKFKNRFWHO-UHFFFAOYSA-N
SMILES [Rb+].[O-][Mn](=O)(=O)=O
Properties
Chemical formula	RbMnO4
Molar mass	204.404
Appearance	purple crystals[1]
Density	3.325 g·cm−3[2]
Melting point	295 °C (decomposes)[2]
Solubility in water	10.6 g·l−1 （19 °C）[3]
Structure
Crystal structure	orthorhombic
Space group	Pnma (Nr. 62)
Lattice constant	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]