Sodium permanganate
A highly soluble permanganate salt used in remediation and etching.
Sodium permanganate (NaMnO₄) is an inorganic salt that closely resembles potassium permanganate but is less favored due to higher production costs. It typically exists as a monohydrate and is highly hygroscopic, absorbing moisture from the air and having a low melting point. Its main advantage is being about 15 times more soluble than potassium permanganate, making it useful when very concentrated MnO₄⁻ solutions are needed.
Unlike potassium permanganate, sodium permanganate cannot be made through the same manganate intermediate route because Na₂MnO₄ does not form. Instead, it is produced via indirect methods, such as converting from KMnO₄ or reacting manganese dioxide with sodium hypochlorite: 2 MnO₂ + 3 NaClO + 2 NaOH → 2 NaMnO₄ + 3 NaCl + H₂O. It dissolves readily in water to form deep purple solutions, and evaporation yields prismatic purple-black crystals of the monohydrate. Because it forms a hydrate (unlike the potassium salt) and is hygroscopic, it is less suitable for analytical chemistry.
Its high solubility makes aqueous solutions useful as a drilled hole debris remover and etchant in printed circuitry, though only to a limited extent. It is gaining use in water treatment for controlling taste, odor, and zebra mussels. The V-2 rocket employed it with hydrogen peroxide to drive a steam turbopump. In environmental remediation, sodium permanganate serves as an oxidizer for in situ chemical oxidation (ISCO) of soil and groundwater contaminated with chlorinated solvents.
- formula
- NaMnO4
- common_form
- Monohydrate (NaMnO4·H2O)
- solubility
- About 15 times more soluble than KMnO4
- key_property
- Hygroscopic, low melting point
- related_compound
- Potassium permanganate
Lore & Background
Sodium permanganate cannot be prepared analogously to the route to KMnO4 because the required intermediate manganate salt, Na2MnO4, does not form. Thus less direct routes are used, including conversion from KMnO4. It can be prepared by the reaction of manganese dioxide with sodium hypochlorite: 2 MnO2 + 3 NaClO + 2 NaOH → 2 NaMnO4 + 3 NaCl + H2O. It dissolves readily in water to give deep purple solutions, evaporation of which gives prismatic purple-black glistening crystals of the monohydrate. The potassium salt does not form a hydrate.
Reader's Guide
Sodium permanganate's significance lies in its high solubility, about 15 times that of potassium permanganate, enabling applications requiring very concentrated MnO4− solutions. It is used as a drilled hole debris remover and etchant in printed circuitry, though with limited utility. It is gaining popularity in water treatment for taste, odor, and zebra mussel control. The V-2 rocket used it in combination with hydrogen peroxide to drive a steam turbopump. As an oxidizer, it is used in environmental remediation of soil and groundwater contaminated with chlorinated solvents via in situ chemical oxidation (ISCO). Its hygroscopic nature makes it less useful in analytical chemistry than its potassium counterpart.
Did You Know?
- Sodium permanganate is about 15 times more soluble than potassium permanganate.
- It absorbs water from the atmosphere and has a low melting point.
- The V-2 rocket used sodium permanganate with hydrogen peroxide to drive a steam turbopump.
- It can be prepared by reacting manganese dioxide with sodium hypochlorite.
More in Sodium Compounds 1-24
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