Lithium TapeCAS #: 7439-93-2

Synonyms 

N/A

Molecular Weight: 6.941 

Appearance: Silvery 

White Melting Point: 180.54 °C 

Boiling Point: 1342 °C 

Density: 0.534 g/cm3 

Solubility in H2O: N/A 

Poisson's Ratio: N/A 

Young's Modulus: 4.9 

GPa Vickers Hardness: N/A 

Tensile Strength: N/A

Thermal Conductivity: 0.848 W/cm/K @ 298-C.2 K 

Thermal Expansion: (25 °C) 46 µm·m-1·K-1 

Electrical Resistivity: 8.55 microhm-cm @ 0 °C 

Electronegativity: 1.0 

Paulings Specific Heat: 0.85 

Cal/g/K @ 25 °C 

Heat of Fusion: 1.10 Cal/gm mole 

Heat of Vaporization: 32.48 K-Cal/gm atom at 1342 °C

Product Introduction: Potassium Metal (K, CAS #: 7439-93-2)

Potassium metal, with the chemical symbol K and CAS number 7439-93-2, is a highly reactive alkali metal belonging to Group 1 of the periodic table. This soft, silvery-white element is characterized by its low density, high reactivity with water and air, and essential role in biological and industrial processes. While pure potassium is rarely used in its elemental form due to its instability, it serves as a critical precursor in the production of potassium compounds and finds specialized applications in metallurgy, chemical synthesis, and research.

Chemical & Physical Properties

Potassium exhibits distinctive properties that define its reactivity and utility:

Physical State: A soft, malleable metal at room temperature, easily cut with a knife to reveal a bright, silvery surface that tarnishes rapidly in air.

Density: Approximately 0.862 g/cm³ at 20°C, making it less dense than water (which causes it to float during reactions).

Melting & Boiling Points: Melts at 63.5°C and boils at 759°C, with a low heat of fusion that facilitates its use in high-temperature processes.

Reactivity: Extremely reactive with water, producing potassium hydroxide (KOH) and hydrogen gas (H₂) in a highly exothermic reaction that can ignite the released hydrogen. It also reacts vigorously with oxygen, forming potassium oxide (K₂O) and potassium peroxide (K₂O₂), and with halogens to form potassium halides (e.g., KCl, KBr).

Electrical Conductivity: A good conductor of electricity and heat, reflecting its metallic bonding structure.

Key Applications

Potassium metal (CAS 7439-93-2) is primarily used as a precursor and in specialized industrial processes, leveraging its strong reducing properties:

Production of Potassium Compounds: Serves as a raw material for manufacturing potassium salts, including potassium chloride (KCl), potassium hydroxide (KOH), and potassium carbonate (K₂CO₃)—compounds essential in fertilizers, food processing, and chemical synthesis.

Metallurgy: Acts as a reducing agent in the extraction of metals such as titanium, zirconium, and hafnium from their oxides, where its high reactivity displaces these metals from their compounds.

Chemical Synthesis: Used in organic chemistry to initiate reactions like the Wurtz coupling, where it promotes the formation of carbon-carbon bonds. It also serves as a drying agent for organic solvents due to its ability to react with trace water.

Heat Transfer Media: In specialized high-temperature systems, potassium alloys (e.g., with sodium) are used as heat transfer fluids in nuclear reactors and industrial furnaces, leveraging their low melting points and high thermal conductivity.

Research & Development: Employed in laboratory settings to study alkali metal reactivity, battery technologies (e.g., potassium-ion batteries), and as a calibration standard for analytical instruments.

Advantages & Limitations

Potassium metal offers unique benefits but requires careful handling due to its reactivity:

Strong Reducing Agent: Its high position in the electrochemical series makes it effective for reducing metal oxides and initiating chemical reactions that weaker reducing agents cannot facilitate.

Precursor Versatility: Enables the synthesis of a wide range of potassium compounds, which are vital in agriculture, medicine, and industry.

Limitations: Extreme reactivity with water and air necessitates strict storage and handling protocols. Its instability in ambient conditions makes it unsuitable for direct use in most consumer or commercial products, limiting applications to controlled industrial and laboratory environments.

Production & Quality Control

Potassium metal is produced through electrolysis, given its high reactivity and difficulty in extraction via chemical reduction:

Electrolysis of Molten Potassium Chloride: The primary method involves electrolyzing molten KCl in a cell with inert electrodes, where potassium ions (K⁺) are reduced at the cathode to form molten potassium metal, while chloride ions (Cl⁻) are oxidized to chlorine gas (Cl₂) at the anode.

Purification: Raw potassium metal is purified by distillation under reduced pressure to remove impurities like sodium and other alkali metals.

Quality control includes elemental analysis via atomic absorption spectroscopy (AAS) or inductively coupled plasma mass spectrometry (ICP-MS) to ensure purity levels (typically 99.5% or higher for industrial grades). Trace impurities, such as sodium, are strictly limited to prevent adverse effects on reactivity.

Safety & Handling

Due to its extreme reactivity, potassium metal requires rigorous safety measures:

Storage: Must be stored under inert liquids (e.g., mineral oil, kerosene) or inert gases (e.g., argon) to prevent contact with air and moisture. Containers must be tightly sealed and labeled as flammable and corrosive.

Handling: Use only in a well-ventilated fume hood with appropriate personal protective equipment (PPE), including flame-resistant gloves, a face shield, and a fire-resistant lab coat. Avoid contact with skin, eyes, and clothing, as even small amounts can cause severe burns.

Reactivity Hazards: Never allow potassium to come into contact with water, acids, or oxidizing agents. Reactions with water can generate enough heat to ignite hydrogen gas, leading to explosions. Have a Class D fire extinguisher (for metal fires) and sand nearby to smother any fires.

Disposal: Dispose of waste potassium by slow reaction with an alcohol (e.g., ethanol) under controlled conditions to neutralize it, following local regulations for hazardous waste. Never discard it in trash or drain systems.

Refer to the product’s Safety Data Sheet (SDS) for detailed emergency response procedures, including first aid for burns and inhalation exposure.

Packaging & Availability

Potassium metal is available in forms designed to minimize reactivity risks:

Ingots or Shavings: Packaged in sealed metal cans or glass ampoules under inert oil or gas, with sizes ranging from 10g for laboratory use to 1kg for industrial applications.

Alloys: Potassium-sodium alloys (e.g., NaK) are available in specialized containers for heat transfer applications, with strict controls on composition and purity.

Availability is restricted to trained professionals and industrial facilities with proper storage and handling infrastructure. High-purity grades (99.9%) are available for research purposes, with additional certification for trace impurity levels.

For technical specifications, safety guidelines, or to inquire about availability, contact our specialized team, which is trained in handling reactive alkali metals.

Health & Safety Information

 Signal Word: Danger 

Hazard Statements: H260-H314 

Hazard Codes: F,C 

Precautionary Statements: P231+P232-P260-P303+P361+P353-P305+P351+P338-P501 

Flash Point: Not applicable 

Risk Codes: 14/15-34 

Safety Statements: 8-43-45 

RTECS Number: OJ5540000 

Transport Information: UN 1415 4.3/PG 1 

WGK Germany: 2 

GHS Pictogram: Image,Image

Chemical Identifiers

 Linear Formula: Li 

Pubchem CID: 3028194 

MDL Number: MFCD00134051 

EC No.: 231-102-5 

Beilstein/Reaxys No.: N/A 

SMILES: [Li] 

InchI Identifier: InChI=1S/Li 

InchI Key: WHXSMMKQMYFTQS-UHFFFAOYSA-N

Packing of Standard Packing: 

Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 735 gallon liquid totes Special package is available on request.