Tantalum pentafluoride (TaF5) is an important reagent in fluorine chemistry. As a strong Lewis acid, a catalyst for fluorination reactions, and a source of tantalum, TaF5 is a useful reagent for the preparation of tantalum-containing materials. Sourcing high-purity TaF5 can be a challenge for research laboratories, microelectronics manufacturers, and specialty chemical producers. If you're looking to buy tantalum pentafluoride online, it's crucial to choose a reliable supplier that offers guaranteed purity, secure packaging, regulatory compliance, and strong traceability.
Alfa Chemistry is your trusted tantalum pentafluoride supplier, providing a convenient, professional, and reliable one-stop shopping experience. It's your ideal choice for sourcing tantalum pentafluoride.
Offering high-purity (99.9%) tantalum pentafluoride with detailed MSDS/COA sheets, safe operation instructions, and professional technical support, we ensure your successful, efficient, and safe use of tantalum pentafluoride in R&D and production.
In this article, we will explore its structure and properties, synthetic routes, potential applications, processing protocols, and selection tips to help you decide whether to use TaF5 in your process or purchase it from your fluorine chemistry station.
Chemical Identity & Fundamental Properties
- The chemical formula is TaF5, also written as F5Ta, with CAS number 7783-71-3.
- Molecular weight: 275.94 g·mol-1.
- In the solid state, it is typically an off-white (or pale) crystalline powder (often described as "white crystalline solid"), with some volatility under mild heating.
- Its solid density is about 4.74 g·cm-3 (room temperature) — this agrees with your Alfa Chemistry data (4.74 g/cm3).
- TaF5 melts around ≈ 96.8 °C and boils or sublimates around 229–230 °C under ambient pressure.
- It is inherently moisture sensitive: it hydrolyzes in the presence of water, generating HF (hydrofluoric acid) and tantalum oxyfluoride species.
- In the gas or melt phase, TaF5 can form fluoride complexes such as hexafluorotantalate anions ([TaF6]-) or higher coordination species, depending on fluoride activity and ligand environment.
Because of this combination of moderate volatility and strong Lewis acidity / fluoride affinity, TaF5 is a prized reagent in fluorine chemistry where controlled generation of fluoride species is needed.
Fig.1 Tantalum pentafluoride and its monohydrate[1].
Synthesis and Purification Methods
TaF5 of 99.9% or higher purity is most often obtained by carefully removing oxide/oxygen and moisture impurities. The common synthesis routes are:
- Halide Exchange/Fluorination of Tantalum Chloride or Oxide
Reaction of TaCl5 (or intermediate tantalum oxychloride) with dry HF typically gives TaF5 and HCl as a byproduct. Reaction conditions are often carefully controlled with dry conditions or an inert atmosphere. This usually involves extreme dehydration and careful acid strength/stoichiometry to limit side hydrolysis. After reaction, sublimation/vacuum fractionation often can be used to purify the TaF5 from residual chloride or oxide.
- Direct Fluorination of Tantalum Metal/Oxide
Direct fluorination from fluorine gas (F2) or a fluorinating agent (ClF3, BrF3, etc.) at high temperature (200-300°C) in an inert container is another method. Tantalum metal is placed in the fluorine (or fluorine/inert gas carrier) and slowly heated/converted to gaseous TaF5, which is condensed.
Use of extreme manufacturing materials (Ni, monel, and fluorine alloys) and thermal control is required. Thermal runaway and decomposition can occur if the process is not strictly controlled. The gas handling and condensation system usually has to be very well controlled but should result in a high-purity product if done properly.
- Precursor Thermal Decomposition/Fluorination
Carbonyl fluoride or other active fluorine donor systems are also used to convert tantalum oxide/oxyfluoride to TaF₅ in heated "dry" conditions in more specialized processes.
- Sublimation/Recrystallization Purification
Crude TaF5 is often sublimated in a vacuum to a high-purity product. TaF5 is volatile at moderate temperatures, and a carefully controlled temperature gradient can often be used to separate higher-boiling and non-volatile impurities. This is often a necessary purification step to semiconductor or catalytic grade purity.
Key Applications and Use Cases
Due to its unique reactivity and volatility, tantalum pentafluoride is widely used in a variety of advanced fields. The following lists its main application areas and reviews how its properties are utilized.
| Application Domain | Role / Mechanism | Notes / Considerations |
| Catalysis / Superacid Systems | TaF5 acts as a strong Lewis acid or fluoride acceptor, especially when combined with HF or other superacid media | It is known to catalyze alkylation, isomerization, Friedel–Crafts type reactions, and fluorination of organic substrates. |
| Fluorination Catalyst & Fluorocarbon Synthesis | It promotes the insertion of fluoride or fluorine into organic molecules under controlled conditions | In fluorocarbon / hydrofluorocarbon synthesis, TaF5 can act as a fluorination promoter in HF media or with halogenated precursors. (lookchem.com) |
| Precursor to Tantalum Oxides / Oxyfluorides | By hydrolysis or thermal transformation, TaF5 can convert to Ta2O5 or TaOF species | Ta2O5 is widely used in dielectric films, capacitors, and high‐k oxides. |
| Semiconductor / Thin Films & CVD / ALD | As a volatile source of Ta in chemical vapor deposition (CVD) or atomic layer deposition (ALD) processes | Because TaF5 can evaporate under moderate heating, it is used to supply tantalum for thin films, barrier layers, or electrode deposition. |
| Metal Deposition / Electrochemical Methods | In molten salt or ionic liquid electrolytes containing TaF5, tantalum metal can be electrodeposited | This is useful in microelectronic or barrier-layer production, where pure metallic Ta films are needed. |
| Separation of Tantalum / Niobium (Analytical / Extraction Chemistry) | TaF5 helps form complex fluoride species that aid in fractional separation of Ta and Nb | For example, in the classic Marignac method, difference in solubility of fluoride complexes is exploited. |
Safe Handling, Storage, and Stability
While TaF5 is a high-value reagent, it requires strict safety practices. Below is a summary of hazards and recommended handling practices.
Hazard and Risk Overview
- Corrosivity and Hydrofluoric Acid Generation: TaF5 rapidly hydrolyzes upon contact with moisture or water to produce hydrofluoric acid (HF), which is highly corrosive and toxic.
- Acute Toxicity: Extremely hazardous by inhalation, ingestion, or in contact with skin or eyes (GHS H314, H302, H312, H332).
- Thermal Decomposition: At elevated temperatures, decomposition may release fluorine or corrosive gases.
- Reactivity: Keep away from strong bases, moisture, strong oxidizing or reducing agents, and incompatible materials.
Personal Protective Equipment (PPE)
- Full-face respirator or air-forced hood (if vapor risk exists)
- Hydrogen fluoride-resistant gloves (e.g., nitrile with a neoprene outer layer)
- Lab coat/acid-resistant suit with full arm protection
- Safety goggles or face shield
Best Practices
- Use a glove box or dry box (inert gas) when weighing or transferring.
- Use a high-flow fume hood for corrosive gases.
- Ensure that all equipment (tubing, valves, containers) is compatible with fluorine/hydrofluoric acid (e.g., nickel, monel, PTFE-lined, Hastelloy, etc.).
- Maintain strict dryness: Purge tubing with inert gas before use.
- Use sealed ampoules or septum technology for transfers whenever possible.
Storage and Disposal
- Store the product in a sealed, inert gas-filled container (e.g., glass or metal ampoule) in a cool, dry, ventilated cabinet away from acids, bases, or moisture.
- Use warning labels and store corrosive chemicals in a separate container. Waste or residues must be neutralized (typically into a stable fluoride salt or silica matrix) in a carefully controlled process according to specialized disposal protocols. Pure residues should be handled by a certified hazardous waste contractor.
Given the hazardous nature of hydrofluoric acid systems, ensuring safety and compatibility is paramount.
Process Tips
- When using TaF5 in catalytic systems, pay attention to the fluoride-to-Ta ratio, HF concentration, and co-ligand or solvent, as these factors influence which Ta-fluoride complex predominates (e.g., [TaF6]-, [TaF7]2-).
- In vapor deposition or sublimation applications, a stable temperature gradient should be maintained to avoid premature condensation or decomposition.
- Before introducing TaF5, all reactors or lines should be thoroughly predried, for example, by high-temperature vacuum bakeout.
- In mixed systems (e.g., TaF5 + other metal fluorides), ensure compatibility of complexation behavior and avoid unwanted cross-reactions. Gradual heating and cooling avoids thermal shock or runaway hydrolysis.
- Monitor for trace moisture infiltration or leakage—even trace amounts can degrade performance.
Frequently Asked Questions (FAQ)
1. What is the advantage of tantalum pentafluoride over other fluoride acids or Lewis acids?
A: TaF5 offers a combination of strong fluoride affinity, volatility under moderate heating, and ability to form stable anionic fluorotantalate species. In many catalytic or deposition systems, this dual character (catalyst + volatile reagent) is hard to match with simpler fluoride acids.
2. Can I use TaF5 in aqueous systems or in water?
A: No, TaF5 hydrolyzes vigorously in the presence of water, producing HF and oxyfluoride species. It must be handled under strictly anhydrous conditions.
3. Is TaF5 stable at room temperature?
A: In a dry, sealed container, it is stable at room temperature. However, exposure to moisture or humidity rapidly degrades it, so good packaging and storage are essential.
4. What kind of containers or materials are safe to use with TaF5?
A: In general, fluorine-resistant metals (nickel, monel, and Hastelloy) or passivated alloys and fluoropolymer linings (PTFE, FEP) are preferred. Glass can be used if properly passivated, but one must avoid any surfaces that may react or degrade.
5. How do I dispose of excess or waste TaF5?
A: Neutralization must be carried out with extreme caution, often by controlled gradual hydrolysis under alkaline conditions, converting to stable fluoride salts. Ultimately, dispose of it via licensed hazardous waste facilities.
6. Can I buy tantalum pentafluoride online in small (gram-level) quantities?
A: Yes, many suppliers offer gram-scale packaging with inert sealing. However, due to its hazardous nature, shipping and regulatory compliance may limit some shipping destinations or require special handling.
7. What differentiates a high-quality tantalum pentafluoride supplier?
A: Key differentiators include rigorous purity and impurity reporting, moisture control in packaging, safe and compliant logistics, traceability, and technical support to users.
Please browse our product list of fluorinated catalysts. If you do not see the product you are looking for, please contact our technical team.
Reference
- Ungerer M.J., et al. (2019). "DFT modelling of tantalum pentafluoride extraction with phosphorus-based extractants – A molecular dynamics study." Journal of Physics and Chemistry of Solids. 135, 109121.
Please kindly note that our products and services are for research use only.
