Fluorocarbonate

A carbonate fluoride, fluoride carbonate, fluorocarbonate or fluocarbonate is a double salt containing both carbonate and fluoride. The salts are usually insoluble in water, and can have more than one kind of metal cation to make more complex compounds. Rare-earth fluorocarbonates are particularly important as ore minerals for the light rare-earth elements lanthanum, cerium and neodymium. Bastnäsite is the most important source of these elements. Other artificial compounds are under investigation as non-linear optical materials and for transparency in the ultraviolet, with effects over a dozen times greater than Potassium dideuterium phosphate.^[1]

Related to this there are also chlorocarbonates and bromocarbonates. Along with these fluorocarbonates form the larger family of halocarbonates. In turn halocarbonates are a part of mixed anion materials. Compounds where fluorine connects to carbon making acids are unstable, fluoroformic acid decomposes to carbon dioxide and hydrogen fluoride, and trifluoromethyl alcohol also breaks up at room temperature. Trifluoromethoxide compounds exist but react with water to yield carbonyl fluoride.