Preparation of entropy-stabilized fluoride phases of fluoroite structure by coprecipitation from aqueous solutions

Using the method of co-precipitation from aqueous solutions of nitrates, nano-sized polysubstituted solid solutions containing from 3 to 8 di- and trivalent cations in different quantitative ratios, with the general formula MRF, where M = Ca, Sr, Ba, Pb, R = La, Gd, Dy, Yb, n = 3 and 4, m = 0, 1, 2 and 4 and x varies from ~0.07 to ~0.3 for different cation compositions, were obtained. All of them retain the fluorite structure (structural type CaF, space group Fm3m). The possibilities of precipitation of mixed solid solutions in different combinations of cations and using different fluorinating agents are considered. It is shown that the obtained solid solutions are medium- and high-entropy phases.