The Synthesis of Crystalline Hydrated Double Carbonates of Rare Earth Elements and Sodium

Crystalline hydrated double carbonates of rare-earth elements and sodium were obtained by adding sodium carbonate solutions to rare-earth chloride solutions. The formula of the precipitates was determined to be LnNa(CO3)2·6H2O (Ln=La, Ce, Nd, Sm, Gd, Dy, and Y). The products have similar X-ray powder diffraction patterns, which were indexed assuming a tetragonal symmetry. The cell parameters of the products were calculated, they decrease linearly with the decrease in the ionic radii of the rare-earth elements.