Permanganate

Permanganate

Names
Systematic IUPAC name Permanganate
Identifiers
CAS Number	14333-13-2
3D model (JSmol)	Interactive image
ChEBI	CHEBI:25939
ChemSpider	22811
PubChem CID	24401
UNII	2BL953CCZ2
CompTox Dashboard (EPA)	DTXSID90912340
InChI InChI=1S/Mn.4O/q;;;;-1 Key: NPDODHDPVPPRDJ-UHFFFAOYSA-N
SMILES [O-] [Mn](=O)(=O)=O
Properties
Chemical formula	MnO− 4
Molar mass	118.934 g·mol−1
Conjugate acid	Permanganic acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

A permanganate (/pərˈmæŋɡəneɪt, pɜːr-/)^[1] is a chemical compound with the manganate(VII) ion, MnO⁻
₄, the conjugate base of permanganic acid. Because the manganese atom has a +7 oxidation state, the permanganate(VII) ion is a strong oxidising agent. The ion is a transition metal ion with a tetrahedral structure.^[2] Permanganate solutions are purple in colour and are stable in neutral or slightly alkaline media. The exact chemical reaction depends on the carbon-containing reactants present and the oxidant used. For example, trichloroethane (C₂H₃Cl₃) is oxidised by permanganate ions to form carbon dioxide (CO₂), manganese dioxide (MnO₂), hydrogen ions (H⁺), and chloride ions (Cl⁻).^[3]

8MnO⁻
₄ + 3C
₂H
₃Cl
₃ → 6CO
₂ + 8MnO
₂ + H⁺
+ 4H
₂O + 9Cl⁻

In an acidic solution, permanganate(VII) is reduced to the pale pink manganese(II) (Mn²⁺) with an oxidation state of +2.

8 H⁺
+ MnO⁻
₄ + 5 e⁻ → Mn²⁺ + 4 H₂O

In a strongly basic or alkaline solution, permanganate(VII) is reduced to the green manganate ion, MnO²⁻
₄ with an oxidation state of +6.

MnO⁻
₄ + e⁻ → MnO²⁻
₄

In a neutral solution, however, it gets reduced to the brown manganese dioxide MnO₂ with an oxidation state of +4.

2 H₂O + MnO⁻
₄ + 3 e⁻ → MnO₂ + 4 OH⁻