Lantanoidien

Lanthanoids, also known as lanthanides, 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 period. The lanthanoids are characterized by their similar chemical properties, which are due to the gradual filling of the 4f electron subshell. This series of elements is often referred to as the "rare earth elements" due to their relatively low abundance in the Earth's crust.

The lanthanoids are named after lanthanum, the first element in the series, which was discovered in 1839 by Carl Gustaf Mosander. The term "lanthanoid" was coined by the German chemist Carl Auer von Welsbach in 1885. The lanthanoids are typically silvery-white in appearance and are relatively soft and ductile. They are highly reactive, especially when exposed to air, and quickly form oxides on their surfaces.

The lanthanoids have a wide range of applications in modern technology. They are used in the production of magnets, catalysts, and glass polishers. They are also used in the manufacture of high-strength alloys and as dopants in various materials to enhance their properties. Additionally, some lanthanoids are used in medical applications, such as in the treatment of certain types of cancer.

Despite their name, lanthanoids are not particularly rare. They are more abundant than many other metals, but their extraction and separation from other elements can be challenging and expensive. The lanthanoids are typically found in minerals such as monazite and bastnäsite, which are mined and processed to extract the individual elements.