Lanthanum Oxide La2O3,
Properties
Molecular formula La2O3
Molar mass 325.81 g/mol
Appearance White powder, hygroscopic
Density 6.51 g/cm3, solid
Melting point 2315 'C (2588 K)
Boiling point 4200 'C (4500 K)
Solubility in water Insoluble
CAS No.: 1312-81-8
EINECS No.:215-200-5
spec typical
TREO: 97% min. 98.5%
La2O3/TREO: 99.9% min. 99.95%
CeO2/ TREO: 0.025% max. 0.01%
Pr6O11/TREO: 0.025% max. 0.01%
Nd2O3/TREO: 0.015% max. 0.01%
Sm2O3/TREO: 0.02% max. 0.003%
Y2O3/TREO: 0.01% max. 0.001%
Fe2O3: 0.02% max. 0.008%
CaO: 0.20% max. 0.07%
Cl: 0.10% max. 0.06%
SiO2: 0.03% max. 0.03%
L.O.I.: 3% max. 1.2%
Synthesis
lanthanum oxide crystallizes as several polymorphs.
To produce hexagonal La2O3, a 0.1 M solution of LaCl3 is sprayed onto a preheated substrate, usually made of metal chalcogenides.[3] The process can be viewed as occurring in two steps - hydrolysis followed by dehydration:
2 LaCl3 + 3 H2O → La(OH)3 + 3 HCl
2 La(OH)3 → La2O3 + 3 H2O
An alternative route to hexagonal La2O3 involves precipitation of nominal La(OH)3 from aqueous solution using a combination of 2.5% NH3 and the surfactant sodium dodecyl sulfate followed by heating and stirring for 24 hours at 80 °C:
2 LaCl3+ 3 H2O + 3 NH3 → La(OH)3 + 3 NH4Cl
LaCl3·3H2O → La2O3
Other routes include:
2 La2S3 + 3 CO2 → 2 La2O3 + 3 CS2
2 La2(SO4)3 + heat → 2 La2O3 + 6 SO3
Other cations
Scandium(III) oxide
Yttrium(III) oxide
Actinium(III) oxide
Related compounds Lanthanum aluminium oxide,
LaSrCoO4
Lanthanum oxide is a white amorphous powder. The density of 6.51g/cm3. The melting point of 2217 DEG C. Boiling point is 4200 ºC. Slightly soluble in water, soluble in acid and generates the corresponding salts. Exposed to air is easy to absorb carbon dioxide and water, gradually become lanthanum carbonate. Burning lanthanum oxide hydrate release a lot of heat.
The main application areas for the manufacture of special alloy precision optical glass with high refractive index, optical fiber board, suitable for the camera, camera, microscope lens and senior optical prisms. Also used in the manufacture of ceramic capacitor, piezoelectric ceramic doping agent and X ray luminescence materials with lanthanum oxide powder. Cerium lanthanum phosphorus ore by extraction or by burning or lanthanum nitrate and lanthanum carbonate. Can also be made by lanthanum oxalate heating decomposition can be prepared. Used as catalysts for many reactions, such as doped cadmium oxide catalytic carbon monoxide oxidation reaction, doped palladium catalytic hydrogenation of carbon monoxide to generate methane reaction. Leach into the lithium oxide or zirconium oxide lanthanum oxide ( 1% ) can be used for manufacturing ferrite magnet. Oxidative coupling of methane generation is ethane and ethylene very effective selective catalyst. For the improvement of barium titanate, strontium titanate ( BaTiO3 ) ( SrTiO3 ) of the temperature dependence of ferroelectric and dielectric properties, as well as the manufacture of fiber optics and optical glass.
The physical and chemical properties of lanthanum oxide
Appearance and properties: white solid powder.
Chinese Name: lanthanum oxide
Chinese Name: three two lanthanum oxide
Molecular formula: La2O3
Relative molecular mass: 325.84 lanthanum oxide
Relative density: 6.51 g/mL at 25 °C ( Li
Melting point: 2315 ° C
Boiling point: 4200 ° C
Solubility: soluble in acid, ethanol, ammonium chloride, insoluble in water, ketone.
The use of lanthanum oxide
Mainly used in the manufacture of precision optical glass, optical fiber. Also used in the electronics industry for ceramic capacitor, piezoelectric ceramics doped with agent. Also used for preparing lanthanum boride raw material, the separation of petroleum refining catalyst. Lanthanum oxide handling and storage
Matters needing attention : closed operation, overall ventilation. The operator must go through specialized training, strict compliance with operating procedures. Proposed operators wear for filter type respirators ( half mask ), wear safety glasses, wear anti-static overalls, wear oil resistant rubber gloves. Away from fire, heat, smoking is prohibited in the workplace. The use of explosion-proof ventilation systems and equipment. To prevent steam leakage in the air of workplace. Avoid oxidizing agents, acids, alkali contact. When the filling velocity should be controlled, and a grounding device, prevent the accumulation of static electricity. When moving to light light unloading, prevent damage to packaging and containers. Equipped with the appropriate variety and quantity of fire-fighting equipment and emergency treatment equipment for leakage. May be left empty containers of hazardous material.
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