Linked from
The 8 pages that link to 4f orbital, each with the reason it gives.
ErbiumRelated: Erbium’s partly filled 4f shell creates its characteristic electronic transitions.
DysprosiumRelated: Dysprosium’s unpaired 4f electrons generate its strong magnetic moment.
4f electronBroader topic: A 4f electron is an electron occupying one of these seven orbitals.
Period 6 elementRelated: The 4f subshell fills across the lanthanide portion of period 6.