Yeah. But can I have an ionic compound with a fluoride, a potassium, and a calcium?
I have not heard about this particular compound, but in general - yes, such things happen. They are quite rare, but there are at least three cases worth of remembering:
1. Ammonium iron(II) sulfate AKA Mohr's Salt (NH4
O (rare case of a stable Fe(II) salt which doesn't get oxidized to Fe(III) when exposed to air).
2. Whole class of alums with a general formula XY(SO4
O, where X is a monovalent cation (like Na+
) and Y is a trivalent cation (like Al3+
3. Basic and acidic salts - like NaHCO3
(in which technically H+
plays a role of a cation), or basic copper carbonate Cu2