Hypomanganate

Hypomanganate ion

Hypomanganates or manganates (V) are chemical compounds of manganese with the MnO ₄ ³⁻ anion. They are unstable and easily disproportionate to manganese (IV) oxide and permanganates . The blue color of the hypomanganate ion is typical.

Extraction and presentation

Hypomanganates can be produced by oxidizing manganese (IV) oxide with sodium oxide in a sodium nitrite melt.

${\displaystyle \mathrm {2\ MnO_{2}+3\ Na_{2}O\ {\xrightarrow {+O}}\ 2\ Na_{3}MnO_{4}} }$

A reduction of permanganates or hexavalent manganates with sulfites in a basic environment is also possible.

properties

The MnO ₄ ³⁻ ion gives hypomanganates a characteristic blue color. This is also paramagnetic .

The pK _s value of the hypothetical Hypo permanganic acid is in the protolysis stage 3 for the reaction of [O ₃ Mn (OH)] ² to MnO ₄ ^3- 13.7, which are unknown to the other protolysis because Hypomanganate in acid solution decompose quickly and are only stable in basic solution.

use

Hypomanganates have no technical significance. They are short-lived, non-isolable intermediate products in the production of potassium permanganate .

In oxidation melts for the detection of manganese, hypomanganate is formed instead of green manganate if the oxygen supply is low.

Individual evidence

1. ^ JD Rush, BHJ Bielski: Studies of Manganate (V), - (VI), and - (VII) Tetraoxyanions by Pulse Radiolysis. Optical Spectra of Protonated Forms. In: Inorganic Chemistry. 34, 1995, pp. 5832-5838, doi : 10.1021 / ic00127a022 .
2. ^ J. Strähle, E. Schweda: Jander · Blasius - Introduction to the inorganic-chemical practical course. 14th edition, S. Hirzel Verlag, Stuttgart 1995, ISBN 978-3-77-760672-9 , pp. 186-192.

literature

• AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 , p. 1617.