What is "reederite-"

Reederite-(Y) is a rare mineral with the formula (Na,Mn,Fe)(Y,REE)(CO)(SOF)Cl. It is the only known mineral with fluorosulfate ( fluorosulfonate). "REE" in the formula stands for rare earth elements other than yttrium, that is mostly cerium, with traces of neodymium, dysprosium, lanthanum and erbium. The formula also includes a Levinson suffix "-(Y)" pointing to the dominance of yttrium at the corresponding site. Reederite-(Y) crystallizes in the hexagonal crystal system with the space group P, rarely seen among minerals.