Lithium SulfateCAS #: 10377-48-7

Synonyms

 Dilthium sulfate; Lithiophor; Lithium sulfate, Anhydrous; Lithium sulfate (2:1); Sulfuric acid, dilithium salt; Lithium sulfate solution; Sulfuric acid, lithium salt (1:2)

Compound Formula: Li2O4S 

Molecular Weight: 109.945 

Appearance: White 

Melting Point: 859° C (1,578° F) 

Boiling Point: 1,377° C (2,511° F) 

Density: 2-C.22 g/cm3 

Solubility in H2O: N/A 

Exact Mass: 109.984 

Monoisotopic Mass: 109.984

Product Introduction: Potassium Tetrafluoroborate (KBF₄, CAS #: 10377-48-7)

Potassium tetrafluoroborate, with the chemical formula KBF₄ and CAS number 10377-48-7, is a specialized inorganic compound consisting of potassium cations (K⁺) and tetrafluoroborate anions (BF₄⁻). This odorless, white crystalline solid is celebrated for its exceptional thermal stability, controlled reactivity, and resistance to hydrolysis, making it a valuable asset in metallurgical processes, surface treatment, and chemical synthesis. Its unique combination of fluoride and boron components enables precise, low-risk applications where predictable fluoride release is critical.

Fundamental Chemical & Physical Properties

KBF₄’s utility is rooted in its well-defined characteristics:

Solubility: Sparingly soluble in water (0.48 g/100 mL at 20°C) and insoluble in most organic solvents, which prevents rapid dissolution and ensures sustained performance in aqueous systems.

Thermal Behavior: Melts at 530°C and decomposes above 600°C, releasing boron trifluoride (BF₃) and potassium fluoride (KF). This high thermal threshold allows use in high-temperature industrial processes without premature breakdown.

Moisture Resistance: Non-hygroscopic under standard conditions, maintaining its crystalline form and flowability during storage, unlike many other fluoride salts that absorb water and clump.

Density & Structure: Has a density of 2.49 g/cm³ and a molar mass of 125.90 g/mol, with a cubic crystal lattice that contributes to its mechanical stability and low reactivity.

Chemical Inertness: Resists hydrolysis even in moderately acidic environments, avoiding the aggressive fluoride release seen in more soluble salts like KF, which simplifies handling and reduces corrosion risks.

Industry-Specific Applications

KBF₄’s controlled reactivity makes it indispensable in targeted industrial roles:

Metallurgy: Enhancing Alloy Purity

As a flux in aluminum, magnesium, and copper alloy production, KBF₄ dissolves oxide impurities (e.g., Al₂O₃, MgO) at high temperatures, forming a low-melting slag that separates easily from molten metal. This process improves casting quality, reduces porosity, and enhances mechanical properties in automotive and aerospace alloys. It also prevents re-oxidation of molten aluminum during processing, a critical advantage over chloride-based fluxes that can cause gas porosity.

Electroplating & Surface Engineering

In electroplating baths for nickel, copper, and tin coatings, KBF₄ acts as a conductive additive, ensuring uniform current distribution and smooth, adherent deposits. It adjusts bath pH and complexes metal ions, preventing the formation of insoluble hydroxides that mar finishes. In surface pretreatment, it etches metal oxides (e.g., on steel or aluminum) to create a micro-rough texture, improving adhesion of paints, adhesives, and platings.

Chemical Synthesis: Controlled Fluorination

Serves as a mild fluorinating agent in organic chemistry, enabling selective fluorination of aromatic compounds and pharmaceuticals without the hazards of elemental fluorine or highly reactive fluorides. It is also a precursor for other tetrafluoroborate salts, such as lithium tetrafluoroborate (LiBF₄), a key electrolyte additive in lithium-ion batteries.

Electronics Manufacturing

Used in the etching of silicon wafers and glass substrates for semiconductors and display panels. Its slow, controlled fluoride release allows precise removal of oxide layers (SiO₂) without damaging underlying materials, enabling the fabrication of microscale circuits and high-resolution displays. It also cleans ceramic components in electronics assembly, removing residual fluxes and ensuring reliable electrical performance.

Advantages Over Competing Fluoride Salts

KBF₄ outperforms alternatives in key scenarios:

Controlled Reactivity: Unlike KF (highly soluble, rapid fluoride release) or ammonium tetrafluoroborate (NH₄BF₄, prone to decomposition), KBF₄ delivers gradual, predictable fluoride release, reducing corrosion risks in metal processing and simplifying dosage control.

Thermal Stability: Withstands higher temperatures than sodium tetrafluoroborate (NaBF₄), making it preferable for high-heat applications like aluminum smelting.

Cost-Effectiveness: More affordable than specialty fluorides (e.g., hexafluorosilicates) while offering comparable performance in fluxing and etching, making it suitable for large-scale industrial use.

Safety Profile: Lower acute toxicity than KF and reduced volatility compared to BF₃ gas, minimizing handling risks with proper precautions.

Synthesis & Quality Assurance

KBF₄ is produced via efficient industrial processes:

Direct Reaction: Potassium fluoride (KF) reacts with boron trifluoride (BF₃) in aqueous or organic solvent: 4KF + BF₃ → KBF₄ + 3KF. Excess KF is removed via crystallization, yielding a crude product.

Neutralization Route: Boric acid (H₃BO₃) reacts with hydrofluoric acid (HF) and potassium hydroxide (KOH): H₃BO₃ + 4HF + KOH → KBF₄ + 4H₂O. This method avoids handling toxic BF₃ gas.

Purification involves recrystallization from water or methanol, followed by drying to achieve purity levels of 98–99.5% for industrial grades. High-purity variants (99.9%) undergo additional processing to reduce heavy metal impurities (e.g., Fe, Pb <5 ppm) for electronics applications.

Quality control includes:

Ion chromatography to verify BF₄⁻ content and detect chloride or sulfate impurities.

X-ray fluorescence (XRF) for elemental analysis.

Moisture testing (Karl Fischer) to ensure <0.1% water, critical for preventing hydrolysis in sensitive uses.

Safety & Handling Protocols

Due to its fluoride content, KBF₄ requires careful management:

Toxicity: Inhalation of dust or ingestion can cause fluoride poisoning, leading to respiratory irritation, gastrointestinal distress, or long-term bone effects. Skin/eye contact may cause mild irritation.

Handling: Wear nitrile or PTFE gloves, safety goggles, and a dust mask when handling powders. Use in well-ventilated areas, especially during high-temperature processes where BF₃ gas may be released.

Storage: Keep in tightly sealed HDPE containers in a cool, dry area, separated from strong acids (which generate HF) and reducing agents.

Spill Response: Sweep up dry spills with inert absorbents (e.g., sand); avoid water, which can dissolve fluoride ions. Neutralize with calcium carbonate to form insoluble CaF₂ before disposal.

Refer to the SDS for detailed emergency procedures, including first aid for exposure.

Packaging & Availability

KBF₄ is supplied in formats tailored to industrial needs:

Industrial Grade: 25kg–50kg multi-layer paper bags with polyethylene liners, or 50kg steel drums for bulk handling.

High-Purity Grade: 1kg–10kg sealed plastic containers for electronics and laboratory use, with certification of impurity levels.

Bulk Quantities: 500kg–1,000kg super sacks for large-scale metallurgical operations, with optional moisture barriers.

Custom particle sizes (e.g., fine powder for electroplating, granules for fluxing) are available upon request.

For technical data, pricing, or to discuss application-specific grades, contact our team specializing in inorganic fluorides for industrial and advanced manufacturing sectors.

Health & Safety Information

 Signal Word: Warning 

Hazard Statements: H302 

Hazard Codes: Xn 

Risk Codes: 22 

Safety Statements: N/A 

RTECS Number: OJ6419000 

Transport Information: N/A 

WGK Germany: 1

Chemical Identifiers 

Linear Formula: Li2SO4 

Pubchem CID: 66320 

MDL Number: MFCD00011086 

EC No.: 233-820-4

IUPAC Name: dilithium sulfate 

Beilstein/Reaxys No.: N/A 

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

InchI Identifier: InChI=1S/2Li.H2O4S/c;;1-5(2,3)4/h;;(H2,1,2,3,4)/q2*+1;/p-2 

InchI Key: INHCSSUBVCNVSK-UHFFFAOYSA-L

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.