lanthanum(III) oxalate

Lanthanum Oxalate: Properties, Synthesis, Applications and Storage

Lanthanum oxalate , also known as lanthanum(III) oxalate, is an important rare earth oxalate compound with the chemical formulaLa₂(C₂O₄)₃. Its common hydrate form is lanthanum oxalate decahydrate (La₂(C₂O₄)₃·10H₂O), and it holds the CAS registry number 537-03-1. As a core intermediate in rare earth separation and lanthanum-based material synthesis, this white fine crystalline powder features stable chemical properties and excellent process controllability, widely applied in materials science, chemical industry, environmental treatment and industrial catalysis fields.

Basic Physical and Chemical Properties

Lanthanum oxalate is a sparingly soluble rare earth salt with extremely low solubility in water, which is its most distinctive physical characteristic. It can form complete and stable precipitates in aqueous solutions, laying a solid foundation for efficient separation and purification of lanthanum elements from rare earth mixed solutions. The compound possesses high crystallinity and adjustable purity, with industrial and research grades commonly reaching a purity of 99.99% and above.

In terms of chemical properties, lanthanum oxalate exhibits excellent thermal decomposition performance. It can undergo controllable thermal decomposition and calcination at specific temperatures, quantitatively converting into high-purity lanthanum oxide (La₂O₃) without introducing excessive impurities. This accurate phase transition feature ensures high repeatability in industrial production and laboratory synthesis. Structurally, it belongs to the layered honeycomb crystal system with stable lattice structure, which enables it to serve as an ideal morphology-directing precursor for preparing porous and high-specific-surface lanthanum-based functional materials.

Synthesis Method

The mainstream synthesis of lanthanum oxalate adopts the aqueous solution precipitation method, which is simple, low-cost and high-yield, suitable for both laboratory preparation and large-scale industrial production. The general process is to mix soluble lanthanum salt solutions (such as lanthanum chloride and lanthanum nitrate) with oxalic acid solution under constant temperature and stirring conditions. Through controlled pH value and reaction temperature, uniform lanthanum oxalate crystal precipitates are generated. After standing precipitation, filtering, washing and low-temperature drying, high-purity lanthanum oxalate powder or hydrate products can be obtained. This preparation process effectively avoids impurity contamination and guarantees the high purity and uniform particle size of the final product.

Core Applications

Lanthanum oxalate is an indispensable precursor and intermediate in the rare earth industry and advanced materials research, with diversified application scenarios:

1. Rare Earth Separation and Purification : Relying on its ultra-low water solubility, lanthanum oxalate is widely used for the separation, enrichment and purification of lanthanum elements from complex rare earth raw materials. It can effectively separate lanthanum from other impurity elements, greatly improving the purity of rare earth products, and is a key material in hydrometallurgy of rare earth resources.

2. Precursor of High-Purity Lanthanum Oxide : After high-temperature calcination and oxalate decomposition, lanthanum oxalate can be stably transformed into high-purity lanthanum oxide. The derived lanthanum oxide is widely used in high-refractive-index optical glass, ceramic capacitors, luminescent materials and heterogeneous catalytic supports, and is a core raw material for advanced optoelectronic and ceramic materials.

3. Catalyst Preparation : It serves as a special precursor for fabricating high-performance lanthanum-based catalysts. The oxalate decomposition process can regulate the surface basicity and defect density of catalyst materials, optimizing the catalytic performance of materials in methane oxidative coupling, petroleum cracking and other chemical reactions.

4. Environmental Water Treatment : In recent years, lanthanum oxalate has been applied in advanced water treatment technology. It can be used as a functional modifier and adsorbent precursor to prepare composite materials for efficient phosphate removal in water bodies. It maintains stable adsorption performance in alkaline water environments, solving the passivation problem of traditional metal hydroxide adsorbents.

Storage and Safety Guidelines

For daily storage, lanthanum oxalate needs to be placed in a dry, cool and ventilated environment with sealed packaging, avoiding moisture, direct sunlight and high-temperature conditions to prevent crystal water loss and deliquescence, which may affect product purity and structural stability. In terms of safety operation, lanthanum oxalate is a mild irritant. Operators should avoid inhalation of dust, accidental ingestion and direct long-term contact with skin and eyes. Standard protective equipment is required during material weighing, feeding and experimental operation to ensure safe production and experimental research.

Conclusion

Thanks to its unique low solubility, controllable thermal decomposition, high purity and stable crystal structure, lanthanum oxalate has become a fundamental functional material integrating rare earth purification, oxide preparation, catalyst synthesis and environmental treatment. With the continuous development of advanced materials and rare earth deep processing technology, high-purity lanthanum oxalate will show broader application prospects in optoelectronic materials, green catalysis, environmental protection and new energy fields.