lanthanoiden

Lanthanoiden, also known as lanthanoids, are a series of 15 metallic chemical elements with atomic numbers 57 through 71. They are located in the f-block of the periodic table, specifically in the sixth and seventh periods. The lanthanoids are characterized by their similar chemical properties, which are due to the gradual filling of the 4f electron shell. This similarity in properties is often referred to as the lanthanide contraction.

The lanthanoids are named after lanthanum (La), the first element in the series. The term "lanthanoid" was coined by the German chemist Carl Auer von Welsbach in 1885. The lanthanoids are often grouped with scandium (Sc) and yttrium (Y) as the rare earth elements, although they are not as rare as their name suggests.

The lanthanoids are typically silvery-white metals that tarnish in air. They are relatively soft and malleable, and have high electrical conductivity. The lanthanoids are used in various applications, including catalysts, magnets, and alloys. They are also used in the production of glass, ceramics, and phosphors.

The lanthanoids are not found in nature as free elements, but rather as compounds in minerals such as monazite and bastnäsite. They are typically extracted through a process of mining, crushing, and chemical treatment. The lanthanoids are often separated from each other using ion exchange or solvent extraction techniques.

The lanthanoids have several isotopes, some of which are radioactive. The most stable isotope of each lanthanoid is typically used in commercial applications. The lanthanoids are considered to be relatively non-toxic, but some compounds of the lanthanoids can be harmful if ingested or inhaled.