Difluorides are chemical compounds with two fluorine atoms per molecule (or per formula unit).
In the form of the mineral fluorite it is the major source of commercial fluorine.
It also has an eponymic crystal structure, which is an end member of the spectrum starting from bixbyite and progressing through pyrochlore.
The difluoride of radium is however not well established due to the element's high radioactivity.
Compounds of the form MF2: The bifluorides contain the two fluorine atoms in a covalently bound HF2− polyatomic ion rather than as F− anions.