Potassium manganate facts for kids

Quick facts for kids Potassium manganate
IUPAC name	Potassium manganate(VI)
Identifiers
CAS number	10294-64-1
PubChem	160931
EC number	233-665-2
SMILES	[O-][Mn](=O)(=O)[O-].[K+].[K+
InChI InChI=1S/2K.Mn.4O/q2*+1;;;;2*-1
Properties
Molecular formula	K2MnO4
Molar mass	197.132 g/mol
Appearance	dark green crystals
Density	2.78 g/cm3, solid
Melting point	190 °C
Solubility in water	decomposes
Acidity (pKa)	7.1
Structure
Crystal structure	isomorphous with K2SO4
Coordination geometry	tetrahedral anion
Hazards
Main hazards	oxidizer
NFPA 704	0 1 1 OX
R-phrases	8-36/37/38
S-phrases	17-26-36/37/39
Related compounds
Related compounds	KMnO4 MnO2 K2CrO4 K2FeO4
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

Potassium manganate is a chemical compound. Its chemical formula is K₂MnO₄. It contains potassium and manganate ions.

Properties

Potassium manganate is a green solid. It can disproportionate into potassium permanganate and manganese(IV) oxide. This happens in acidic pH. This reaction, because of its color change, is known as a "chemical chameleon".

Preparation

It is made by reacting manganese(IV) oxide with very hot potassium hydroxide. Sometimes oxygen or potassium nitrate is used as the oxidizing agent. This makes potassium manganate. Normally the potassium manganate is converted to potassium permanganate. Potassium permanganate is more common. Potassium iodide can reduce potassium permanganate to potassium manganate. It can also be made by reacting hot potassium permanganate with potassium hydroxide. This makes oxygen and potassium manganate.

Uses

Potassium manganate does not have many uses. It is mainly made when potassium permanganate is made.

Safety

Potassium manganate is a moderate oxidizing agent. When it is reduced, it can made black or brown stains on glass, clothing, or skin.

Related pages

• Permanganate
• Manganese(VII) oxide

See also

In Spanish: Manganato de potasio para niños