Potassium manganate

Crystal structure
Crystal system	orthorhombic
Space group	Pnma (No. 62)
General
Surname	Potassium manganate
other names	Potassium manganate (VI)
Ratio formula	K 2 MnO 4
Brief description	green solid
External identifiers / databases
EC number	233-665-2
ECHA InfoCard	100.030.592
PubChem	160931
ChemSpider	141385
Wikidata	Q941691
properties
Molar mass	197.13 g mol −1
Physical state	firmly
Melting point	190 ° C (decomposition)
solubility	Decomposes in water; Stable in very strongly alkaline solutions;
safety instructions
H and P phrases	H: 272-315-319-335
	P: 220-261-305 + 351 + 338
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Potassium manganate is an inorganic chemical compound of potassium from the group of manganates .

Extraction and presentation

Potassium manganate can be obtained by reacting potassium permanganate with potassium hydroxide .

{\ displaystyle {\ ce {\ mathrm {4 \ KMnO_ {4} \ +4 \ KOH \ longrightarrow 4 \ K_ {2} MnO_ {4} \ + O_ {2} \ +2 \ H_ {2} O}} }}

It can also be obtained by reacting manganese (II) compounds or manganese (IV) oxide with potassium hydroxide and oxygen or air or by reacting potassium nitrate with potassium carbonate .

{\ displaystyle {\ ce {\ mathrm {2 \ MnO_ {2} \ + O_ {2} \ +4 \ KOH \ longrightarrow 2K_ {2} MnO_ {4} \ + 2H_ {2} O}}}}

{\ displaystyle {\ ce {\ mathrm {MnO_ {2} \ + KNO_ {3} \ + K_ {2} CO_ {3} \ longrightarrow K_ {2} MnO_ {4} \ + KNO_ {2} \ + CO_ { 2}}}}}

properties

Potassium manganate is a green paramagnetic solid with a metallic sheen. It has an orthorhombic crystal structure with the space group Pnma (space group no. 62) . It is stable in alkaline aqueous solution, but in neutral or acidic solution it decomposes into potassium permanganate and manganese (IV) oxide . Template: room group / 62

{\ displaystyle {\ ce {\ mathrm {3 \ K_ {2} MnO_ {4} \ +2 \ H_ {2} O \ longrightarrow 2 \ KMnO_ {4} \ + MnO_ {2} \ +4 \ KOH}} }}

use

It is used as a selective oxidizing agent.

Individual evidence

^ ^A ^b Mary Eagleson: Concise Encyclopedia Chemistry . Walter de Gruyter, 1994, ISBN 978-3-11-011451-5 , p. 889 ( limited preview in Google Book Search).
↑ ^a ^b ^c ^d data sheet Potassium manganate from Sigma-Aldrich , accessed on September 10, 2015 ( PDF ).
↑ ^a ^b ^c R. S. Nyholm and PR Woolliams: Manganates (VI) . In: William L. Jolly (Ed.): Inorganic Syntheses . tape 11 . McGraw-Hill Book Company, Inc., 1968, p. 56-61 (English).
↑ ^a ^b R. DW Kemmitt, RD Peacock: The Chemistry of Manganese, Technetium and Rhenium Pergamon Texts in Inorganic Chemistry . Elsevier, 2013, ISBN 978-1-4831-8762-4 , pp. 809 ( limited preview in Google Book search).
↑ Erwin Riedel, Christoph Janiak: Inorganic Chemistry . Walter de Gruyter, 2011, ISBN 978-3-11-022567-9 , pp. 833 ( limited preview in Google Book search).
↑ Gus J. Palenik: Crystal structure of potassium manganate. In: Inorganic Chemistry . 6, 1967, pp. 507-511, doi : 10.1021 / ic50049a016 .

[Mary_Eagleson-1] A ^b Mary Eagleson: Concise Encyclopedia Chemistry . Walter de Gruyter, 1994, ISBN 978-3-11-011451-5 , p. 889 ( limited preview in Google Book Search).

[Sigma-2] ta sheet Potassium manganate from Sigma-Aldrich , accessed on September 10, 2015 ( PDF ).

[IS11-3] R. S. Nyholm and PR Woolliams: Manganates (VI) . In: William L. Jolly (Ed.): Inorganic Syntheses . tape 11 . McGraw-Hill Book Company, Inc., 1968, p. 56-61 (English).

[R._D._W._Kemmitt,_R._D._Peacock-4] R. DW Kemmitt, RD Peacock: The Chemistry of Manganese, Technetium and Rhenium Pergamon Texts in Inorganic Chemistry . Elsevier, 2013, ISBN 978-1-4831-8762-4 , pp. 809 ( limited preview in Google Book search).

[Erwin_Riedel,_Christoph_Janiak-5] Erwin Riedel, Christoph Janiak: Inorganic Chemistry . Walter de Gruyter, 2011, ISBN 978-3-11-022567-9 , pp. 833 ( limited preview in Google Book search).

[DOI10.1021/ic50049a016-6] Gus J. Palenik: Crystal structure of potassium manganate. In: Inorganic Chemistry . 6, 1967, pp. 507-511, doi : 10.1021 / ic50049a016 .