Cadmium niobium fluoride

Cadmium Niobium Fluoride, 3NbF5.5CdF2.5HF.28H20 or NbsCd5F25. 5HF.28HaO, is obtained in long, transparent prisms by the action of cadmium carbonate on a solution of niobic acid in concentrated hydrofluoric acid. It is insoluble in water. 

Copper Niobium Fluoride, NbFg.2CuF2.HF.9H2O or NbCuF9.HF. 9H20, forms large, dark blue crystals, which are obtained similarly to the cadmium salt. 

Calcium(II), which shows no appreciable complexing, has a distribution coefficient of 147 in 0.5 M perchloric acid and 191 in 0.5 M hydrochloric acid. Strelow. Rethc-meyer, and Bothnia [10] also reported data for nitric and sulfuric acids that showed complexation in some cases. Mercury(II), bismuth(III), cadmium(II), zinc(II), and lead(II) form bromide complexes and are eluted in the order given in 0.1 to 0.6 M hydrobromic acid [11]. Most other metal cations remain on the column. Aluminu-m(III), molybdenum(VI), niobium(V), tin(IV), tantalum(V), uranium(VI), tung-sten(VI), and zirconium(IV) form anionic fluoride complexes and are quickly eluted from a hydrogen-form cation-exchange column with 0.1 to 0.2 M HF [12]. 

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