Reaction between rare earth elements and HFNO2 solution

Rare earth elements react with HFNO₂ solution to produce nitrosylium fluorometallates (NO)_xLnF_x+3. The value of x is 1.0 or 1.5 for light rare earth elements and 0.5 or 1.0 for heavy rare earths. Nitrosylium fluorometallates of rare earth elements can be decomposed into the simple fluoride and nitrosyl fluoride at low temperatures (46–68°C).