Potassium manganate (10294-64-1) Physical and Chemical Properties
Potassium manganate
An inorganic oxidizing salt supplied as a dark green crystalline solid and used industrially as an intermediate in potassium permanganate production and for controlled oxidation steps.
| CAS Number | 10294-64-1 |
| Family | Manganates (inorganic salts) |
| Typical Form | Dark green crystalline solid |
| Common Grades | EP |
Potassium manganate is an inorganic ionic salt composed of potassium cations and the tetravalent manganate anion; its stoichiometric formula is \(\ce{K2MnO4}\). Structurally it contains a central manganese atom formally in the +6 oxidation state coordinated to four oxido ligands, giving the tetraoxomanganate(6−) framework often written as the \(\ce{MnO4^2-}\) anion paired with two \(\ce{K+}\) counterions. The solid is typically a dark green crystalline or powder form consistent with extended ionic lattices and strong Mn–O multiple-bond character in the anionic unit.
Electronically the manganate anion is relatively oxidizing and supports redox interconversion with other manganese oxyanion states; it is stabilized in strongly alkaline media and is prone to disproportionation or further oxidation under acidic or oxidizing conditions. As an inorganic salt it is intrinsically polar and ionic, giving rise to good solvation in polar protic solvents; however, solution behavior is dominated by redox and hydrolytic reactivity rather than simple dissolution thermodynamics. Industrial relevance is primarily as an intermediate oxidant in the manufacture of higher-oxidation-state manganese reagents and as a technical oxidizing agent in chemical processes.
Common commercial grades reported for this substance include: EP.
Basic Physical Properties
Density
No experimentally established value for this property is available in the current data context.
Melting or Decomposition Point
No experimentally established value for this property is available in the current data context.
Solubility in Water
No experimentally established numeric solubility is available in the current data context. Qualitatively, the compound is ionic and would be expected to dissolve in polar solvents; practical aqueous handling is complicated because the manganate anion is chemically reactive in water. Manganate solutions are stable under strongly alkaline conditions but undergo hydrolysis and redox transformations (including disproportionation to other manganese oxyanions and/or formation of manganese oxides) when the pH is lowered or when they contact reducing or proton-donating media. For process design, dissolution protocols should consider both the desired concentration and the pH/stability window for the \(\ce{MnO4^2-}\) species.
Solution pH (Qualitative Behavior)
No single numeric solution pH is available in the current data context. Qualitatively, aqueous solutions of \(\ce{K2MnO4}\) are characteristically alkaline because the manganate anion acts as a base relative to its conjugate acids (manganic acid species such as \(\ce{H2MnO4}\) are referenced in nomenclature). The anion is most stable in strongly alkaline solution; acidification shifts equilibria toward disproportionation and formation of lower- or higher-oxidation-state manganese species (for example, conversion to permanganate-like or manganese oxide products), accompanied by changes in color and oxidizing power.
Chemical Properties
Acid–Base Behavior
The manganate anion \(\ce{MnO4^2-}\) behaves as a base relative to protonated manganese oxyacids (synonymous nomenclature includes manganic acid, \(\ce{H2MnO4}\), in salt descriptions). In strongly alkaline media the anion remains the predominant species; on acidification, protonation and redox reactions occur that alter the manganese oxidation state distribution. These processes are pH-dependent and can be rapid under strongly acidic conditions, leading to conversion into different manganese oxyanions and precipitated oxides under processing or disposal conditions. Control of pH is therefore critical to maintain the desired chemical form in solution.
Reactivity and Stability
Potassium manganate is an oxidizing agent and can intensify or initiate combustion when in contact with organic or otherwise combustible materials. It is chemically reactive toward reducing agents and organic substrates; contact with such materials can result in vigorous oxidative reactions. The substance is described as decomposable by water under certain conditions and is more stable in alkaline environments. GHS-style hazard classifications reported for the substance indicate oxidizing solid behavior (oxidizer), skin and eye irritation potential, and possible respiratory irritation. Relevant hazard statements reported include: H272 (May intensify fire; oxidizer), H315 (Causes skin irritation), H319 (Causes serious eye irritation), and H335 (May cause respiratory irritation). Thermal or acid-induced decomposition can produce manganese oxides and other manganese-containing residues; process design should minimize contact with acids and organic reducing matter and include inerting/separation measures where appropriate.
Molecular and Ionic Parameters
Formula and Molecular Weight
- Molecular formula: \(\ce{K2MnO4}\)
- Molecular weight: 197.132
- Exact mass: 196.845114
- Monoisotopic mass: 196.845114
Constituent Ions
- Cation: \(\ce{K+}\)
- Anion: \(\ce{MnO4^2-}\)
Additional computed descriptors from structure analysis: topological polar surface area 80.3, hydrogen bond donor count 0, hydrogen bond acceptor count 4, rotatable bond count 0, heavy atom count 7, and formal charge 0 (overall neutral salt). Complexity is reported as 62.
Molecular identifiers: SMILES "[O-][Mn](=O)(=O)[O-].[K+].[K+]", InChI InChI=1S/2K.Mn.4O/q2*+1;;;;2*-1, and InChIKey XKYFHUXZPRFUTH-UHFFFAOYSA-N.
Identifiers and Synonyms
Registry Numbers and Codes
- CAS number: 10294-64-1
- EC number: 233-665-2
- UNII: 5PI213D3US
- DSSTox Substance ID: DTXSID10893107
- InChIKey:
XKYFHUXZPRFUTH-UHFFFAOYSA-N - InChI:
InChI=1S/2K.Mn.4O/q2*+1;;;;2*-1 - SMILES:
[O-][Mn](=O)(=O)[O-].[K+].[K+]
Synonyms and Common Names
Reported synonyms and common names include (selection of recorded names): Potassium manganate; Potassium manganate(VI); Dipotassium manganate; Manganic acid (H2MnO4), dipotassium salt; Manganic acid (H2MnO4), potassium salt (1:2); Dipotassium; dioxido(dioxo)manganese; Potassium manganic acid.
Industrial and Commercial Applications
Functional Roles and Use Sectors
Potassium manganate is employed as an oxidizing agent in chemical manufacture and is used industrially as an intermediate in the production of higher-oxidation-state manganese reagents. Industry processing sectors include basic inorganic chemical manufacturing. It is used in manufacturing contexts where controlled oxidation and subsequent conversion to permanganate or manganese oxides are required.
Commercial grades: EP.
Typical Application Examples
- Intermediate in the industrial synthesis of potassium permanganate.
- Technical oxidizing agent in chemical processes where a strong inorganic oxidant is appropriate.
Reported aggregated U.S. production volumes (annual, pounds): 2019: 25,245,141 lb; 2018: 25,256,707 lb; 2017: 25,045,431 lb; 2016: 24,682,672 lb. These figures reflect large-scale industrial use and are relevant for supply-chain and procurement assessments.
If a concise application summary is required beyond the functional roles above, selection of this substance for a given process should be based on its oxidizing strength, pH-dependent stability, and compatibility with process materials and waste-treatment constraints.
Safety and Handling Overview
Health and Environmental Hazards
Potassium manganate is an oxidizer and an irritant. Reported hazard classes include Oxidizing Solids, Skin Irritation, Eye Irritation, and Specific Target Organ Toxicity (single exposure) categories consistent with respiratory irritation potential. Health effects associated with manganese exposure include neurotoxic outcomes at sufficient doses and durations; manganese species can be systemic toxicants that affect the central nervous system and other organs. Reported toxicological observations identify manganese as capable of producing neurological dysfunction (manganism) with chronic exposure, and potential reproductive toxicity is noted in classification summaries. Exposure routes of concern include inhalation and ingestion; skin and eye contact can cause irritation.
Occupational exposure guideline values reported in the available context include maximum allowable concentrations and threshold limit values expressed as manganese: maximum allowable concentration \(0.2\ \mathrm{mg}\,\mathrm{m}^{-3}\) as Mn (inhalable fraction) and \(0.02\ \mathrm{mg}\,\mathrm{m}^{-3}\) as Mn (respirable fraction) (German Research Foundation (DFG) reporting); threshold limit values reported include \(0.02\ \mathrm{mg}\,\mathrm{m}^{-3}\) as Mn (respirable fraction) and \(0.1\ \mathrm{mg}\,\mathrm{m}^{-3}\) as Mn (inhalable fraction). These values are presented as reported descriptors and should be reconciled with applicable local occupational exposure limits and hygiene requirements.
First-aid measures (summary): flush eyes with water for several minutes if exposed; for skin contact, rinse with water and wash with soap; if inhaled, move to fresh air and provide supportive care; if swallowed, do not induce vomiting—seek medical attention. Emergency response for fire involves recognizing oxidizer properties and isolating from combustible materials.
For environmental considerations, avoid release to waterways; manganese oxyanions and particulates can have ecotoxicological effects and require appropriate waste management.
Storage and Handling Considerations
Store in a cool, dry, well-ventilated area away from organic materials, reducing agents, and combustibles. Because potassium manganate is an oxidizer, segregate storage from flammable and easily oxidizable substances and maintain appropriate secondary containment. Use corrosion-resistant tools and containers compatible with alkaline, oxidative materials. In process and handling, implement engineering controls to limit dust and aerosol generation; provide local exhaust ventilation where powders or aerosols may form.
Personal protective equipment should include chemical-resistant gloves, eye/face protection, and appropriate respiratory protection when airborne exposure cannot be adequately controlled. Avoid ingestion and prolonged skin contact. For spill or leak response, avoid mixing with incompatible materials; collect material for disposal in accordance with local regulations and minimize environmental release.
For detailed hazard, transport and regulatory information, users should refer to the product-specific Safety Data Sheet (SDS) and local legislation.
