Indium Triacetate: Properties, Uses & Handling FAQ

Indium triacetate is a versatile indium(III) coordination compound widely used as a soluble indium precursor in nanocrystal synthesis, thin-film deposition, and organometallic chemistry.

Chemical Name

Indium(III) acetate (Indium triacetate)

Molecular Formula

In(CH₃COO)₃ / C₆H₉InO₆

Molecular Weight

291.94 g/mol

CAS Number

25114-58-3

Appearance

White to off-white crystalline powder

Primary Application

Indium source for colloidal nanocrystal and semiconductor thin-film synthesis

SKU

I192310

What Is Indium Triacetate and What Are Its Key Chemical Properties?

Indium triacetate, systematically named indium(III) acetate and often abbreviated In(OAc)₃, is the trivalent indium salt of acetic acid. Its molecular formula is C₆H₉InO₆ with a molecular weight of approximately 291.94 g/mol (CAS 25114-58-3). The compound presents as a white to off-white crystalline powder at room temperature.

As a metal acetate, indium triacetate is moderately soluble in polar coordinating solvents such as dimethyl sulfoxide (DMSO), dimethylformamide (DMF), and hot acetic acid, while exhibiting limited solubility in common non-polar solvents. The acetate ligands coordinate to the In³⁺ center and can be displaced by stronger ligands, making the compound a reactive and accessible source of indium ions in solution-phase chemistry.

Indium triacetate is moisture-sensitive and may partially hydrolyze upon prolonged exposure to atmospheric humidity, generating indium hydroxide species. It should therefore be stored under dry conditions, ideally in a tightly sealed container with desiccant.

What Are the Main Research and Synthesis Applications of Indium Triacetate?

Indium triacetate is one of the most widely employed soluble indium precursors in materials chemistry and nanotechnology. Key application areas include:

• Colloidal Nanocrystal Synthesis: In(OAc)₃ is a standard precursor for the preparation of indium-based quantum dots and nanomaterials, including indium phosphide (InP), indium arsenide (InAs), and related core/shell semiconductor nanocrystals. Its moderate reactivity allows controlled nucleation and growth when combined with appropriate chalcogenide or pnictide precursors.
• Thin-Film Deposition: The compound serves as an indium source in chemical bath deposition (CBD), spin-coating, and spray pyrolysis techniques for fabricating transparent conducting oxide films and photovoltaic absorber layers.
• Organometallic and Coordination Chemistry: Indium triacetate is used to synthesize more complex indium coordination complexes and as a Lewis-acid catalyst in select organic transformations.
• Sol-Gel and Ceramic Processing: It functions as a precursor in sol-gel routes toward indium oxide (In₂O₃) powders and coatings, relevant to gas-sensor and optoelectronic device fabrication.

Its combination of commercial availability, defined stoichiometry, and solution processability makes indium triacetate a preferred starting material compared to indium halides in many wet-chemical protocols.

How Should Indium Triacetate Be Stored and Handled Safely?

Storage: Store indium triacetate in a tightly closed container in a cool, dry, well-ventilated area away from moisture and incompatible materials such as strong acids, strong bases, and oxidizing agents. Storage temperatures around 2–25 °C are generally appropriate; check the certificate of analysis for product-specific recommendations. Use desiccant to prevent moisture ingress.

Personal Protective Equipment (PPE): When handling indium triacetate, wear appropriate PPE including nitrile gloves, safety goggles, and a laboratory coat. If there is a risk of generating dust or aerosols, use a NIOSH-approved dust mask or work within a fume hood.

Health Hazards: Indium compounds can be harmful if inhaled or ingested. Chronic occupational exposure to indium compounds has been associated with pulmonary effects in industrial settings; however, typical laboratory-scale handling with proper precautions poses a significantly lower risk. Always consult the Safety Data Sheet (SDS) before use.

Disposal: Do not dispose of indium-containing waste down the drain. Collect waste in labeled containers and dispose of in accordance with local, regional, and national regulations governing heavy-metal-containing laboratory waste.

How Does Indium Triacetate Compare to Other Common Indium Precursors?

Researchers often choose among several indium precursors depending on their synthetic requirements. The table below summarizes key comparisons:

• Indium triacetate vs. Indium chloride (InCl₃): InCl₃ is highly soluble in water and many polar solvents and is widely used, but the chloride counter-ion can interfere with certain reactions or product purification steps, particularly in nanocrystal synthesis where halide passivation or contamination is undesirable. In(OAc)₃ avoids halide introduction.
• Indium triacetate vs. Indium nitrate (In(NO₃)₃): Indium nitrate is also highly water-soluble but introduces nitrate, an oxidizing anion that can complicate reductive synthesis environments. Acetate is a non-oxidizing, relatively inert counter-ion.
• Indium triacetate vs. Indium acetylacetonate (In(acac)₃): In(acac)₃ is more thermally stable and less reactive, making it suitable for high-temperature vapor-phase processes, while In(OAc)₃ offers higher reactivity at moderate temperatures in solution-phase synthesis.

Overall, indium triacetate occupies a practical middle ground: it is reactive enough for solution-phase chemistry at moderate temperatures, introduces no problematic anions, and is commercially available in high purity grades.

Quality, Purity, and What to Check Before Use

For research applications, the purity of indium triacetate is critical, as trace metal impurities can significantly affect nanocrystal size distribution, optical properties, and device performance. When selecting a grade of In(OAc)₃, consider the following:

• Purity grade: For demanding applications such as quantum dot synthesis or thin-film electronics, select reagent-grade or higher purity material. Review the certificate of analysis (CoA) for the specific lot to confirm metal purity and the absence of critical impurities.
• Water content: Some commercial lots may be supplied as hydrated forms. Verify whether the product is anhydrous or hydrated, as this affects stoichiometric calculations and reactivity.
• Appearance check: Before use, visually inspect the powder. Discoloration or clumping may indicate moisture uptake or decomposition; in such cases, the lot should be tested or discarded.
• Lot-to-lot consistency: For reproducibility in nanocrystal syntheses, it is advisable to use material from the same production lot or to characterize new lots before use in critical experiments.

Aladdin Scientific's indium triacetate (SKU: I192310) is available with documented purity specifications. Contact our technical support team for the most current CoA or to discuss grade suitability for your application.

Frequently asked questions

What solvents are suitable for dissolving indium triacetate?

Indium triacetate dissolves most readily in polar coordinating solvents such as DMSO, DMF, and hot glacial acetic acid. It has limited solubility in non-polar solvents like toluene or hexane. For nanocrystal syntheses that require non-polar media, oleylamine or oleic acid are commonly used as both solvents and ligands to form soluble indium complexes in situ.

Is indium triacetate air- and moisture-stable, and how should it be handled on the bench?

Indium triacetate is moderately sensitive to atmospheric moisture and can undergo slow hydrolysis to form indium hydroxide species upon prolonged exposure. While brief exposure during weighing is generally tolerable, extended handling should be performed in a dry environment or a glove box when high moisture sensitivity is critical. Always reseal the container promptly and store with desiccant.

Can indium triacetate be used directly as a Lewis acid catalyst in organic reactions?

Yes, In(OAc)₃ can act as a mild Lewis acid catalyst in certain organic transformations, including Friedel-Crafts type reactions, allylations, and cyclization reactions. However, its Lewis acidity is relatively moderate compared to stronger indium Lewis acids such as InBr₃ or InCl₃. Researchers should evaluate reaction scope and catalyst loading empirically for their specific substrate.

What is the typical temperature range used when employing indium triacetate as a nanocrystal precursor?

In hot-injection and heat-up nanocrystal syntheses using indium triacetate, reaction temperatures typically range from approximately 150 °C to 300 °C depending on the target material and ligand system. For InP quantum dots, temperatures around 180–280 °C are commonly reported in the literature. The exact temperature profile influences nucleation kinetics and the final particle size distribution.

Does Aladdin Scientific offer indium triacetate in multiple package sizes?

Aladdin Scientific lists indium triacetate under SKU I192310. For information on available quantities, packaging options, and current pricing, please visit the product page on our website or contact our sales team directly. Bulk quantities may be available upon request.

References

1. Reiss, P.; Protière, M.; Li, L. Core/Shell Semiconductor Nanocrystals. Small 2009, 5, 154–168. (General reference for indium-based nanocrystal precursor use.) doi:10.1002/smll.200800841
2. Joung, S.; Yoon, S.; Han, C.-S.; Kim, Y.; Jeong, S. Facile synthesis of uniform large-sized InP nanocrystal quantum dots using tris(trimethylsilyl)phosphine. Nanoscale Res. Lett. 2012, 7, 93. (Example of In(OAc)₃ use in InP QD synthesis.) doi:10.1186/1556-276X-7-93
3. Downs, A. J. (Ed.) Chemistry of Aluminium, Gallium, Indium and Thallium. Blackie Academic & Professional, 1993. (Textbook-level reference for indium coordination chemistry.)

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