Lithium Polysilicate SolutionCAS #: 12627-14-4

Synonyms

 Silicic acid lithium salt, Lithium silicate, Lithium silicon oxide, Aqueous lithium silicate (20% - 25% in H2O)

Compound Formula: Li2Si5O11 

Molecular Weight: 330.3 

Appearance: Clear liquid 

Melting Point: N/A 

Boiling Point: N/A 

Density: 1.16 g/mL (25 °C) 

Solubility in H2O: Soluble 

Exact Mass: 329.860703 g/mol 

Monoisotopic Mass: 329.860703 g/mol

Product Introduction: Sodium Hexafluorophosphate (NaPF₆, CAS #: 12627-14-4)

Sodium hexafluorophosphate, with the chemical formula NaPF₆ and CAS number 12627-14-4, is a key fluorinated inorganic salt widely utilized in electrochemical systems, industrial synthesis, and advanced materials science. Composed of sodium cations (Na⁺) and hexafluorophosphate anions (PF₆⁻), this white crystalline compound is prized for its high solubility in polar organic solvents, moderate thermal stability, and efficient ionic conductivity—properties that make it a versatile material in sodium-ion batteries (SIBs), supercapacitors, and specialty chemical processes. Its balance of performance, cost-effectiveness, and compatibility with diverse systems has solidified its role as a staple in both industrial manufacturing and cutting-edge research.

Chemical & Physical Properties

NaPF₆ exhibits a set of characteristics that underpin its utility across diverse fields:

Solubility: Highly soluble in polar organic solvents such as acetonitrile, propylene carbonate (PC), and dimethyl carbonate (DMC), with solubility exceeding 1.2 M in typical electrolyte blends. It is sparingly soluble in water (approximately 6.5 g/100 mL at 20°C), limiting its use in aqueous systems but enhancing compatibility with non-aqueous electrolytes.

Thermal Stability: Decomposes at temperatures above 540°C under inert conditions, though hydrolysis occurs in the presence of moisture, releasing hydrogen fluoride (HF) and phosphoric acid derivatives. This thermal resilience allows its use in moderate-temperature processes, such as electrolyte formulation for batteries and industrial catalysis.

Hygroscopicity: Moderately hygroscopic, absorbing moisture from the air over time, which can trigger partial hydrolysis. This necessitates storage in dry environments to maintain purity, particularly in moisture-sensitive applications like battery electrolyte production.

Density & Structure: Has a density of 2.36 g/cm³ and a molar mass of 167.95 g/mol, with a cubic crystal structure that promotes efficient ion dissociation in solution. The PF₆⁻ anion’s symmetry enhances ionic mobility, contributing to high conductivity in organic solvents.

Ionic Conductivity: Delivers ionic conductivities of 9–13 mS/cm in 1 M organic solvent solutions, supporting efficient charge transport in electrochemical devices like SIBs and supercapacitors.

Key Applications

Sodium hexafluorophosphate (CAS 12627-14-4) is integral to numerous technological and industrial processes:

Sodium-Ion Batteries (SIBs): Serves as a primary electrolyte salt in SIBs, a promising alternative to lithium-ion batteries due to sodium’s natural abundance and low cost. Its high solubility in organic solvents enables the formation of conductive electrolytes that facilitate sodium ion transport between electrodes. In laboratory tests, NaPF₆-based electrolytes support SIBs with hard carbon anodes and layered oxide cathodes to achieve 1,500+ cycles with 75% capacity retention, making them suitable for grid storage and low-cost energy applications.

Supercapacitors: Used in electrolytes for sodium-based supercapacitors, where its high ionic conductivity and wide electrochemical window (up to 3.8 V in organic solvents) enable high power density and rapid charge-discharge cycles. These supercapacitors achieve energy densities of 12–18 Wh/kg, with 95% capacitance retention after 100,000 cycles, ideal for regenerative braking and backup power systems.

Ionic Liquid Synthesis: Acts as a precursor in the production of sodium-based ionic liquids, which are used as green solvents in chemical synthesis and as electrolytes in high-temperature batteries. These ionic liquids exhibit low volatility and high thermal stability, with NaPF₆-derived variants finding use in CO₂ capture and biocatalysis.

Organic Synthesis: Functions as a fluorinating agent and electrolyte additive in electrochemical reactions, facilitating the synthesis of fluorinated organic compounds. It promotes selective fluorination in pharmaceutical intermediates and agrochemicals, achieving yields of 70–85% in key reactions.

Electroplating: Employed in metal plating baths for depositing noble metals (e.g., gold, palladium) onto substrates. The PF₆⁻ anion helps regulate metal ion solubility, improving coating uniformity and adhesion, which is critical for electronics and decorative applications.

Advantages & Limitations

NaPF₆ offers distinct benefits alongside practical considerations:

Cost-Effectiveness: More affordable than specialty fluorinated salts like sodium bis(fluorosulfonyl)imide (NaFSI), making it suitable for large-scale applications such as grid storage batteries and industrial electroplating.

Compatibility: Works with a wide range of organic solvents and electrode materials, including hard carbon, sodium vanadate, and Prussian blue analogs, providing flexibility in SIB design.

Established Supply Chain: Mature manufacturing processes ensure consistent availability and quality, supporting reliable industrial-scale production.

Limitations: Hydrolysis in moist environments generates toxic HF, requiring strict moisture control during handling and storage. Its lower thermal stability compared to NaFSI may restrict use in high-temperature applications, and it exhibits lower ionic conductivity than advanced alternatives, limiting performance in fast-charging batteries.

Synthesis & Quality Control

NaPF₆ is produced through efficient industrial processes:

Metathesis Reaction: Sodium fluoride (NaF) reacts with phosphorus pentafluoride (PF₅) in anhydrous hydrogen fluoride (HF) solvent: NaF + PF₅ → NaPF₆.

Purification: The crude product is purified via recrystallization from anhydrous acetonitrile or PC to remove residual impurities, achieving industrial-grade purity (>99.0%) with metal ion concentrations <10 ppm.

Quality control includes:

Ion chromatography to verify PF₆⁻ purity and detect contaminants like fluoride (F⁻) or phosphate (PO₄³⁻).

Inductively coupled plasma mass spectrometry (ICP-MS) to measure trace metals (K, Ca, Fe <5 ppm).

Karl Fischer titration to ensure moisture content <100 ppm, critical for preventing hydrolysis in electrolyte applications.

Safety & Handling

Proper handling of NaPF₆ is essential to mitigate risks:

Toxicity: Inhalation of dust or contact with moisture can release HF, causing severe irritation to the respiratory system and skin. Chronic exposure to fluoride ions may affect bone health, requiring adherence to occupational limits (e.g., 2.5 mg/m³ for fluoride in the U.S.).

Handling: Use in well-ventilated fume hoods with humidity control (<20% RH). Wear PTFE gloves, splash goggles, and a dust respirator to prevent contact.

Storage: Keep in airtight, moisture-proof containers (e.g., stainless steel or HDPE) in a cool, dry area, separated from strong acids and reducing agents.

Disposal: Classified as hazardous waste due to fluoride content; dispose of in accordance with local regulations (e.g., EPA RCRA in the U.S.). Neutralize spills with calcium carbonate to form insoluble CaF₂.

Refer to the product’s Safety Data Sheet (SDS) for detailed emergency protocols.

Packaging & Availability

NaPF₆ is available in forms tailored to industrial and research needs:

Industrial Grade: 25kg–50kg drums for large-scale electrolyte production and electroplating.

Research Grade: 100g–5kg bottles in moisture-barrier packaging for laboratory use, ensuring high purity.

Solution Form: Pre-dissolved in organic solvent blends (e.g., 1.0 M in PC/acetonitrile) in 1L–20L containers for immediate use in battery assembly.

Global production is led by manufacturers in China, Europe, and the United States, with annual capacity exceeding 8,000 tons. High-purity grades (99.9%) are available for advanced electronics and research applications.

For technical specifications, custom formulations, or supply chain insights, contact our team specializing in fluorinated chemicals and battery materials.

Health & Safety Information 

Signal Word: Danger 

Hazard Statements: H318-H335 

Hazard Codes: C 

Precautionary Statements: P261-P280-P305 + P351 + P338 

Risk Codes: N/A 

Safety Statements: N/A 

RTECS Number: N/A 

Transport Information: NONH for all modes of transport 

WGK Germany: 3 

GHS Pictogram: Image,Image

Chemical Identifiers

 Linear Formula: Li2Si5O11 

Pubchem CID: 16212725 

MDL Number: MFCD00197874 

EC No.: 235-730-0

IUPAC Name: dilithium; bis[[[oxido(oxo)silyl]oxy-oxosilyl]oxy]-oxosilane 

SMILES: [Li+].[Li+].[O-][Si](=O)O[Si](=O)O[Si](=O)O[Si](=O)O[Si](=O)[O-] 

InchI Identifier: InChI=1S/2Li.O11Si5/c;;1-12(2)8-14(5)10-16(7)11-15(6)9-13(3)4/q2*+1;-2 

InchI Key: WJZHQBRAMOCCLJ-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.