Barium permanganate

Structural formula
General
Surname	Barium permanganate
other names	Barium manganate (VII)
Molecular formula	Ba (MnO 4 ) 2
Brief description	brown purple to black solid
External identifiers / databases
CAS number 7787-36-2 EC number 232-110-1 ECHA InfoCard 100.029.191 PubChem 24587 Wikidata Q3701934
properties
Molar mass	375.20 g mol −1
Physical state	firmly
density	3.77 g cm −3
solubility	625 g / l at 20 ° C
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 272-332-302 P: ?
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Barium permanganate is an inorganic chemical compound of barium from the group of permanganates .

Extraction and presentation

Barium permanganate can be obtained by reacting barium manganate with carbon dioxide in water or with sulfuric acid.

${\displaystyle \mathrm {3\ BaMnO_{4}+2\ CO_{2}\longrightarrow Ba(MnO_{4})_{2}+2\ BaCO_{3}+MnO_{2}} }$

${\displaystyle \mathrm {3\ BaMnO_{4}+2\ H_{2}SO_{4}\longrightarrow 2\ BaSO_{4}+Ba(MnO_{4})_{2}+MnO_{2}+2\ H_{2}O} }$

Barium permanganate can also be made from silver permanganate and barium chloride . High purity barium can be obtained by reaction of potassium permanganate with aluminum sulfate are prepared, wherein the formed Aluminiumpermanganat with a stoichiometric amount of barium hydroxide is reacted.

properties

Barium permanganate is a brown-violet to black solid that is sparingly soluble in water. It is a strong oxidizing agent and decomposes to barium manganate at high temperatures above 280 ° C.

${\displaystyle \mathrm {Ba(MnO_{4})_{2}\longrightarrow BaMnO_{4}+MnO_{2}+O_{2}} }$

It is thermally stable up to 180 ° C and decomposes in two stages between 180–350 and 500–700 ° C. The decomposition takes place quickly from temperatures of 200–220 ° C, is exothermic and the activation energy is 113 kJ / mol. The decomposition can be described as follows.

${\displaystyle \mathrm {2\ Ba(MnO_{4})_{2}\longrightarrow 2\ BaMnO_{3}+2\ MnO_{2}+3\ O_{2}} }$

${\displaystyle \mathrm {4\ BaMnO_{3}\longrightarrow 4\ BaO+2\ Mn_{2}O_{3}+O_{2}} }$

${\displaystyle \mathrm {4\ MnO_{2}\longrightarrow 2\ Mn_{2}O_{3}+O_{2}} }$

Investigations have shown that decomposition begins slowly at 160 ° C and that this temperature continues to drop due to the action of UV light or X-rays (activation). Crystal defects and impurities play a role in the decomposition temperature and the decomposition mechanism. The compound does not occur as a hydrate, a trihydrate is known as a mixed crystal only in a matrix of barium perchlorate trihydrate.

Barium permanganate has an orthorhombic crystal structure with the space group Fddd (space group no. 70) (a = 14.749, b = 11.896, c = 7.414 Å , Z = 8). The average O-Mn distances are 1.74 and 1.61 Å.

use

By reacting barium permanganate with sulfates , permanganates of various metals can be produced.

Individual evidence

1. ↑ ^{a b} Richard P. Pohanish: Sittig's Handbook of Toxic and Hazardous Chemicals and Carcinogens . William Andrew, 2011, ISBN 1-4377-7870-4 , pp. 323 ( limited preview in Google Book search).
2. ↑ ^{a b c d} Georg Brauer: Handbook of preparative inorganic chemistry . 3., reworked. Edition. tape III . Enke, Stuttgart 1981, ISBN 3-432-87823-0 , pp. 1585 .
3. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Inorganic Compounds, pp. 4-50.
4. ↑ Entry on barium permanganate in the GESTIS substance database of the IFA , accessed on July 10, 2016(JavaScript required) .
5. ↑ ^{a b c d} Laszlo Kotai, Istvan Gacs, Istvan E. Sajo, Pradeep K. Sharma, Kalyan K. Banerji: ChemInform Abstract: Beliefs and Facts in Permanganate Chemistry - An Overview on the Synthesis and the Reactivity of Simple and Complex Permanganates. In: ChemInform. 42, 2011, S. no, doi : 10.1002 / chin.201113233 .
6. ^ Richard C. Ropp: Encyclopedia of the Alkaline Earth Compounds . Newnes, 2012, ISBN 0-444-59553-8 , pp. 895 ( limited preview in Google Book Search).
7. ↑ EG Prout, PJ Herley: THE THERMAL DECOMPOSITION OF BARIUM PERMANGANATE. In: The Journal of Physical Chemistry. 65, 1961, p. 208, doi : 10.1021 / j100820a005 .