la3

La3 typically denotes the trivalent lanthanum ion, La3+, in inorganic chemistry. Lanthanum is the first element of the lanthanide series, with the atomic number 57. In most salts and coordination compounds, lanthanum adopts the +3 oxidation state, making La3+ the common cation form encountered in solution and solid salts such as LaCl3 or La2O3.

In aqueous solution, La3+ forms hydrated complexes, commonly described as [La(H2O)n]3+. The ion is prone to hydrolysis as pH increases, leading to species such as La(OH)2+, La(OH)2+, and eventually insoluble La(OH)3 at higher pH. La3+ readily forms oxoanions with anions like phosphate, carbonate, and sulfate, and can participate in coordination chemistry with various ligands, often displaying high coordination numbers typical of rare-earth cations.

La3+ is predominantly obtained from minerals such as monazite and bastnasite. Extraction involves ore concentration, followed by chemical processing and solvent extraction to separate lanthanum from other rare-earth elements. The refined La3+ salts and oxides serve as precursors for various applications.

Common uses of lanthanum compounds include catalysts (lanthanum oxide and related materials function as basic catalysts in organic synthesis and petroleum processing), dopants in ceramics and glass, and components in phosphors and scintillators. Lanthanum carbonate, a La3+-containing salt, is used medically as a phosphate binder in chronic kidney disease.

Safety and environmental considerations apply to all lanthanum compounds. They are generally of low acute toxicity but can be irritating, and mining and processing of rare-earth elements have associated environmental impacts.