This compound belongs to the class of inorganic compounds known as homogeneous alkali metal compounds. These are inorganic compounds containing only metal atoms,with the largest atom being a alkali metal atom.
External Descriptors
a cation
1. Djoumbou Feunang Y, Eisner R, Knox C, Chepelev L, Hastings J, Owen G, Fahy E, Steinbeck C, Subramanian S, Bolton E, Greiner R, and Wishart DS. ClassyFire: Automated Chemical Classification With A Comprehensive, Computable Taxonomy. Journal of Cheminformatics, 2016, 8:61.
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Application Protocols
Item-specific tested applications and protocols are not provided for this product.
General research usage notes (literature/guidance; not item specifications)
Preparation of K+-containing solutions: Dissolve the appropriate potassium salt (e.g., KCl, K-gluconate, KH2PO4/K2HPO4) in deionized water to the desired ionic strength and pH. Filter sterilize (0.22 μm) for cell-related workflows.
Electrophysiology: Internal pipette solutions often use 100–140 mM K+ with defined buffering (e.g., K-HEPES) and Mg2+/EGTA balance; external solutions use 2–6 mM K+.
Enzyme assays: Replace Na+ with K+ where the enzyme shows K+-dependence (e.g., pyruvate kinase); maintain consistent ionic strength across assays.
Chromatography: Potassium phosphate buffers are widely used in ion-exchange and SEC; filter and degas to avoid baseline noise.
Important
The exact concentration, form, and any stabilizers for this product are not specified; consult the CoA/SDS. Adjust protocols to the verified composition and purity of the supplied material.
Biological Roles
Overview (literature; for research use only)
Potassium ion (K+) is the principal intracellular cation in most cells and is essential for maintaining membrane potential, cell volume, and enzyme activity. Intracellular [K+] is typically ~120–150 mM, while extracellular [K+] is ~3–5 mM in many mammalian systems, establishing the K+ gradient fundamental to bioelectric phenomena.
Key functions
Membrane potential and excitability: K+ conductance through voltage-gated and inward-rectifier potassium channels shapes action potentials and resting potentials. The Na+/K+-ATPase maintains the transmembrane gradient.
Enzyme activation: K+ activates or stabilizes numerous enzymes (e.g., pyruvate kinase, ribozymes) and influences ribosomal function and protein synthesis.
Osmoregulation: Balances osmotic pressure and contributes to cell volume regulation via K+/Cl− cotransport.
Nucleic acid structure: Stabilizes G-quadruplex DNA/RNA structures more effectively than Na+ due to ionic radius/coordination preferences.
Experimental considerations
Use potassium-based buffers/salts to mimic intracellular conditions (e.g., K-gluconate, KCl). Trace Na+ and divalent cations (Ca2+, Mg2+) can modulate channel behavior; control carefully.
In electrophysiology and transport assays, maintain defined K+ activities (accounting for ionic strength and activity coefficients) rather than just concentrations.
Note
No medical or clinical claims are made or implied. This information supports laboratory research design.
Buffer Applications
Relevance
K+ is commonly used as the cation in biological buffers and salt systems to better reproduce intracellular conditions and to modulate enzyme or channel function.
Common potassium-based buffers/salts (literature; examples, not item specs)
Potassium phosphate (KP i): pKa2 ~7.21 at 25 C; effective pH range ~6.2–8.2. Suitable for enzyme assays and chromatography. Prepared by mixing KH2PO4 and K2HPO4.
K-HEPES: Zwitterionic buffer where K+ is the counterion for the acid/base forms; useful near pH 7.2–7.6 with minimal temperature dependence.
K-MOPS/K-TAPS: Good buffering near pH 7.2 and 8.4, respectively.
KCl and K-gluconate: Adjust ionic strength and provide chloride-free intracellular-like solutions.
Practical tips
Select K+ rather than Na+ to minimize sodium-dependent transport effects and to stabilize certain protein/nucleic acid structures.
Control total ionic strength (I) when titrating buffers; K+ activity differs slightly from concentration due to activity coefficients.
For electrophysiology, internal solutions often contain 100–140 mM K+ with low Cl− alternatives to reduce chloride conductance; external solutions typically 2–6 mM K+ to maintain physiological gradients.
Item-specific
No buffer formulation or concentration is specified for this item; refer to the CoA/SDS for any provided solution details.
Green Alternatives
Perspective
The environmental profile of a potassium ion source depends largely on the counterion and solvent system. Selecting greener anions/solvents and minimizing energy use are the main levers.
Greener choices (literature/guidance)
Counterion selection: Prefer benign anions (Cl−, acetate, phosphate, carbonate) over PF6− or perchlorate where performance allows.
Solvent selection: Favor water or bio-based solvents (e.g., ethanol) instead of high-toxicity polar aprotics (DMF, NMP). Use complexing agents (e.g., 18-crown-6) judiciously and recover them when possible.
Process intensification: Aqueous or solvent-free phase-transfer methods can reduce solvent load.
Energy efficiency: Conduct reactions at ambient temperature/pressure if feasible; microwave or flow approaches can lower energy consumption.
Illustrative comparison (general; not item-specific)
Aqueous K2CO3 vs KOtBu in THF
Greenness: Aqueous K2CO3 typically safer/greener; KOtBu/THF is flammable and generates hazardous waste.
Performance: KOtBu is stronger base and faster in E2/alkylation; K2CO3 may require longer times or higher temperature.
K-phosphate buffers vs KPF6 electrolytes
Greenness: Phosphate buffers are benign and widely acceptable; PF6− salts present persistence/toxicity concerns.
Recommendation
Start with water and benign potassium salts for screening. Escalate only if performance necessitates less green options.
Pharmaceutical Uses
Scope
No therapeutic claims. The following pertains to formulation/excipient roles of potassium-containing materials in pharmaceutical research and manufacturing.
Excipient/counterion roles (literature)
Salt formation: Potassium salts of APIs (e.g., potassium clavulanate, potassium guaiacolsulfonate) can improve solubility or stability relative to free acids.
Buffering and tonicity: Potassium phosphate and KCl are used to adjust pH and osmolarity in parenteral and oral formulations; selection is driven by compatibility and regulatory monographs.
Lyophilization aids: Potassium salts can serve as bulking agents or pH adjusters in freeze-dried biologics.
Coatings and controlled release: Potassium-containing osmotic agents contribute to osmotic pump tablets.
Regulatory/quality considerations
Use compendial grades (e.g., USP/EP) of specific potassium salts where required. Control residual metals, endotoxin/bioburden (for parenterals), and particle burden.
Assess API–counterion pairing for polymorphism and hygroscopicity; potassium salts may differ in hydrate formation versus sodium analogs.
Item-specific
Grade/purity and pharmacopeial status are not specified for this item; consult the CoA/Spec Sheet and SDS for the supplied form and suitability in research formulation studies.
Physical Properties
Item-specific (from Product Data)
Appearance: Not specified for this item; refer to CoA/Spec Sheet.
Molecular Weight: Not specified for this item; refer to CoA/Spec Sheet.
Literature/general physicochemical information (for reference; not item specifications)
Hydration number in water: commonly 4–7 in first shell, depending on model and conditions (literature)
Standard atomic weight of K (elemental): 39.0983 (literature). For solutions/salts containing K+, molar mass depends on the counterion.
Solubility: The free ion is not isolated; potassium salts with common anions (Cl−, NO3−, AcO−) are generally highly water soluble; lipophilicity is negligible (literature)
LogP: Not applicable to an inorganic cation; effective partitioning strongly disfavors nonpolar phases without an ion-pairing agent (literature)
pKa: Not applicable (no acidic/basic protons); basicity in gas phase is not typically used for solution chemistry (literature)
Conductivity: Potassium electrolytes provide high molar conductivity in water; limiting molar conductivity λ°(K+) ~73.5 S·cm2·mol−1 at 25 C (literature)
Diffusion coefficient in water: D(K+) ~1.96 × 10−5 cm2 s−1 at 25 C (literature)
Practical notes
Physical constants (bp/mp) do not apply to an isolated ion; the relevant measurable properties are those of specific potassium salts or solutions.
Quality and Grades
Item-specific (from Product Data)
Grade/Purity: Not specified for this item; refer to CoA/Spec Sheet.
Guidance on grades (general; not item specifications)
Analytical/Reagent grade potassium salts: Typically low levels of trace metals and anions; suitable for analytical chemistry and routine synthesis.
Bio/Cell culture grade: Controlled endotoxin/bioburden and defined levels of trace contaminants to minimize biological variability. For electrophysiology or ion-channel work, high purity and low trace Na+/divalent metals may be important.
HPLC/LC–MS grade electrolytes: Low UV background and metal contaminants; often specified for mobile phase additives (e.g., potassium phosphate). Ensure filtered, low-particulate content.
What to check on the CoA
Counterion identity and assay (e.g., as K+ % or as salt assay)
Water content (Karl Fischer) and residual solvents: Not specified for this item; refer to CoA/Spec Sheet.
Trace metal profile (e.g., Na, Ca, Mg, Fe) relevant for enzymology and catalysis: Not specified for this item; refer to CoA/Spec Sheet.
pH of specified solutions, conductivity, and UV absorbance (if applicable)
Stabilizers/additives
Not typically required for inorganic potassium salts; if present (e.g., anti-caking agents in solids or biobuffers in solutions), they should be declared on the CoA.
Reaction and Applications
As a monovalent hard cation, K+ primarily serves as a counterion and electrolyte rather than a reactive species. Its role can be crucial in multiple contexts.
Representative application domains (literature)
Organic synthesis as counterion: Potassium bases (e.g., K2CO3, KHCO3, KOtBu, K3PO4, KOH) promote eliminations, condensations (e.g., Claisen, Knoevenagel), and SNAr reactions. K+ influences aggregation and solubility vs. Na+ or Li+ analogs.
Phase-transfer chemistry: Quaternary ammonium or crown ether complexes of K+ enable reactions of inorganic nucleophiles in organic media (e.g., KCN, KI, KF with 18-crown-6).
Catalysis: K+ additives modulate catalyst speciation and basicity; common in base-promoted cross-couplings (e.g., Suzuki–Miyaura with K3PO4 or K2CO3) and alcohol dehydrogenations (KOtBu).
Materials and electrochemistry: Potassium electrolytes (e.g., KPF6, KFSI) for K-ion batteries; K+ serves as the charge carrier analogous to Li+ in Li-ion systems.
Biochemical assays: K+ is required to maintain enzyme activity for many kinases and polymerases, and to set ionic strength/membrane potentials in model systems.
Practical considerations
Choose potassium counterions to balance solubility and basicity. K+ forms strong complexes with 18-crown-6, enabling anion “nakedness” and rate enhancements.
Drying: Hygroscopic potassium salts should be dried under vacuum at mild temperature when water-sensitive chemistry is planned; avoid over-drying for hydrates that can decompose or lose crystallinity.
Reaction Conditions
General guidance (literature; tailor to specific potassium salt and reaction)
Solvents: Polar aprotic (DMF, DMSO, MeCN) enhance ion separation, increasing basicity/nucleophilicity of potassium salts; protic solvents (alcohols, water) moderate reactivity and favor ionic conduction.
Temperature: Many K+-mediated base reactions proceed at 20–80 C; stronger bases (KOtBu, KHMDS) allow room temperature transformations, while milder bases (K2CO3) often require heating.
Additives: 18-crown-6 or cryptands complex K+ to generate more reactive “naked” anions; phase-transfer catalysts (quats) enable biphasic reactions.
Stoichiometry: Typical 1.1–2.0 equivalents of base relative to the acidic substrate; adjust based on acidity and competitive side reactions.
Time/yield: Strong-base alkylations and eliminations can reach completion within minutes to hours at ambient to 50 C with good to excellent yields; carbonate/phosphate-mediated couplings may require several hours at 60–100 C. Consult literature precedent for the specific substrate system.
Workup considerations
Quench exothermically and cautiously (e.g., alcohol then water) for strong bases; neutralize to pH 6–8.
Remove crown ethers by aqueous extraction or silica plug; monitor for residual potassium by ICP-OES if catalytic metal contamination is critical.
Note
Conditions depend on the exact potassium reagent; the present product’s specific form is not detailed. Verify with the CoA/SDS.
Safety and Handling
Item-specific (from Product Data)
GHS Classification: Not specified for this item; refer to SDS.
Signal Word: Not specified for this item; refer to SDS.
H-Statements: Not specified for this item; refer to SDS.
Pictograms: Not specified for this item; refer to SDS.
Storage Conditions: Room temperature.
General safety guidance (literature/practice; defer to SDS for the supplied form)
Identity and hazards depend on the counterion and matrix (dry salt vs aqueous solution). Most common potassium salts (e.g., KCl, K2SO4) are of low acute toxicity but can be irritants; strong bases (e.g., KOH) are corrosive. Always consult the SDS for the exact product form.
Personal protective equipment: Laboratory coat, safety glasses, and appropriate gloves. Use in a well-ventilated area; avoid inhalation of dust/aerosols and contact with eyes/skin.
Incompatibilities: Strong oxidizers or reducers may be incompatible depending on the counterion. For potassium base-containing materials, avoid acids, halogenated solvents, and moisture.
First aid (generic): If inhaled, move to fresh air; seek medical attention if symptoms persist. In case of skin/eye contact, rinse with water for at least 15 minutes. If ingested, rinse mouth; do not induce vomiting; seek medical advice.
Spill/cleanup: Avoid dust generation. Collect mechanically or absorb solution with inert material; dispose according to local regulations.
Special risks: None specific to K+ itself. Do not assume biocompatibility; research use only.
Solvent Selection
This product is an inorganic cation and not a solvent. Solvent selection pertains to the medium used to dissolve the associated potassium salt or to prepare K+-containing solutions.
General guidance (literature)
Aqueous media: Most common potassium salts are highly soluble in water; water is the default solvent for electrolyte and buffer preparation.
Protic polar solvents: Methanol, ethanol, and isopropanol may dissolve certain potassium salts; solubility depends on the anion.
Aprotic polar solvents: Solubility varies widely. Crown ethers (e.g., 18-crown-6) or cryptands can complex K+ to enhance solubility in acetonitrile, THF, DMF, DMSO.
Nonpolar solvents: Direct solubility is poor; ion pairing or phase-transfer agents (e.g., lipophilic tetraphenylborate salts) can render K+ compatible with low-polarity media.
When to choose K+ systems vs Na+
Enzyme specificity and ionic radius: K+ can better mimic physiological conditions for many enzymes and ion channels compared to Na+.
Phase-transfer and reactivity: Potassium bases (KOtBu, K2CO3) often provide different reactivity/solubility profiles than sodium analogs.
Practical tips
Match the counterion and solvent to the application (e.g., K-phosphate in water for biochemical buffers; KPF6 in polar organics for electrochemistry). Verify solubility and conductivity before scale-up.
Storage and Reconstitution
Item-specific (from Product Data)
Storage Conditions: Room temperature.
Shipped In: Not specified for this item; refer to CoA/Spec Sheet.
Appearance/Form: Not specified for this item; refer to CoA/Spec Sheet.
General guidance (applicability depends on supplied form; defer to CoA/SDS)
Solid potassium salts: Store tightly closed in a dry place at ambient temperature. For hygroscopic salts, use desiccant and minimize exposure to humid air. If clumping occurs, gently break up and verify mass by drying if required.
Aqueous solutions: Store in clean, inert containers at room temperature unless otherwise stated; for biological work, consider refrigeration (2–8 C) to limit bioburden and use within a defined period. Monitor for precipitation if temperature fluctuates.
Reconstitution: Not specified for this item; refer to CoA/Spec Sheet. If the product requires reconstitution, dissolve in a compatible solvent (commonly water for inorganic potassium salts) to the desired concentration, mixing gently until fully homogeneous. Adjust pH only if appropriate for the counterion present.
Freeze–thaw: Typically not required for simple electrolyte solutions; avoid repeated freeze–thaw that can change concentration by precipitation or container contraction.
Disposal
Dispose of potassium-containing solutions according to local regulations; avoid release to the environment for problematic counterions (e.g., perchlorate, PF6−).
Structure and Identity
Brief: Potassium ion (K+) is a monovalent inorganic cation, ubiquitous in chemistry and biology as a counterion and electrolyte.
Item-specific (from Product Data)
Product Name: Potassium ion
CAS: 24203-36-9
CID: 813
InChIKey: 244982
SMILES: Not specified for this item; refer to CoA/Spec Sheet.
Literature/General identity (for reference; not item specifications)
Molecular formula (cation): K+
Exact monoisotopic mass (39K): 38.9637 g/mol (literature)
Standard atomic weight (potassium, IUPAC): 39.0983 g/mol (literature)
Charge: +1; oxidation state: +1
Electronic configuration: [Ar] (for K+, 4s electron removed) (literature)
Coordination: Typically 6–8 (up to 12) in solids/complexes; prefers hard O-donor ligands (literature)
2D structural description (literature)
A single potassium center bearing a formal +1 charge; no covalent bonds. In 2D depictions, represented as the symbol K with a plus sign (K+). No stereochemistry, rings, or functional groups are present.
Notes
As an isolated ion, structure is defined by electrostatics and solvation. In solids and solutions, K+ exists with a solvation shell (e.g., [K(H2O)n]+ in water) or as a counterion in salts. Always consult the CoA to confirm the exact form supplied (solid salt, solution, counterion context).
Synthetic Utility
Concept
K+ functions as a counterion whose size and solvation characteristics influence base strength, nucleophile reactivity, and phase behavior. Choice of potassium vs sodium/lithium can materially impact outcomes.
Key contexts (literature)
Base-mediated transformations: KOtBu, KHMDS, K2CO3, K3PO4, and KOH are ubiquitous for E2 eliminations, alkylations, condensations (Claisen, Dieckmann), and SNAr substitutions. Larger K+ cation often yields more “naked” anions in polar aprotic media.
Halide exchange/Finkelstein-like processes: KI can accelerate substitution reactions via better leaving-group exchange and iodide nucleophilicity; crown ethers further enhance reactivity by complexing K+.
Fluorinations/desilylations: KF (often with 18-crown-6 or crypt-222) for desilylation or as fluoride source in nucleophilic fluorination.
Cross-coupling: In Suzuki–Miyaura and Buchwald–Hartwig protocols, K2CO3 or K3PO4 act as bases and sequestrate HX, affecting catalyst speciation and kinetics.
Heterogenous catalysis/supports: K+ promoters in oxide catalysts modify acidity/basicity (e.g., K-doped alumina for dehydrogenations), and K+ salts induce phase-transfer-like behavior in biphasic systems.
Select counterions balancing solubility, safety, and waste minimization.
Target Specificity
Not typically applicable.
This product is an inorganic ion, not an antibody, enzyme, or targeted biological reagent. No target specificity, clone, isotype, or species reactivity information is applicable.
Item-specific target/epitope data: Not specified for this item; refer to CoA/Spec Sheet if any biological conjugation or targeting information is provided in a specialized format.
よくある質問
How should this product be stored?
Store at room temperature.
What are the CAS number, molecular formula and molecular weight?
The CAS Number is 24203-36-9, the molecular formula is K?, and the molecular weight is 39.098 g/mol. InChIKey NPYPAHLBTDXSSS-UHFFFAOYSA-N.
What documentation is provided?
Available product documentation, including Certificates of Analysis (COA), Safety Data Sheets (SDS), and specification sheets, is shown in the product document area. Document availability and access follow the current site policy.
Products are supplied to verified businesses, institutions, and qualified professionals for research and development use only. Not for use in humans, animals, diagnosis, or therapy.
