Lanthanum oxide (La2O3) is a chemical compound known for its high melting point, refractive index, and dielectric constant. Here are some detailed facts and historical context about Lanthanum oxide:
The element Lanthanum was discovered in 1839 by Carl Gustav Mosander, a Swedish chemist, who identified it as an impurity in Cerium nitrate. Lanthanum oxide was not immediately isolated but was part of the broader study of Rare earth elements. The name "Lanthanum" derives from the Greek word "lanthanein," meaning "to lie hidden," which reflects its tendency to be found in combination with other elements.
Lanthanum oxide is primarily produced by thermal decomposition of Lanthanum carbonate or by the reaction of Lanthanum nitrate with sodium hydroxide. The resulting hydrate is then calcined to yield the oxide:
La(NO3)3 + 3 NaOH → La(OH)3 + 3 NaNO3 La(OH)3 → La2O3 + 3 H2O (at high temperatures)
While Lanthanum oxide is considered to have low toxicity, precautions should be taken when handling the powder to avoid inhalation or ingestion due to possible respiratory or gastrointestinal irritation.