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(element with atomic numbers 57 through 71)

A lanthanide (sometimes abbreviated as Ln) is element lanthanum (atomic number 57) or one of the 14 following elements, through atomic number 74. Their isotopes have mass numbers in the 130 to 180 range.

They are trans-iron elements, thus clearly were created by one or more of the processes that produce them, such as the r-process and s-process. They make up the bulk of the rare ea­rth elements.