Phosphorus-containing compounds of pollucite structure and radiochemical problems

New pollucite-like phosphorus-containing compounds with cesium and uni-, bi-, and trivalent cations (Li; Mg, Mn, Co, Ni, Cu, Zn, Cd, Sr, Ba; Al, Cr, Fe), many of which can be present in various combinations in wastes from radiochemical processes, were synthesized. The individual phases obtained were characterized by X-ray phase analysis and IR spectroscopy. The symmetry of the unit cells of the phosphorus-containing compounds decreases relative to the silicon analog (pollucite natural mineral) from Ia3d to I4132. The behavior of the compounds on heating to 1000°C, under hydrothermal conditions at 90°C, in aqueous systems (distilled water and seawater) at 25°C, and in a CsCl melt at 680°C was studied. The chemical and phase composition of the samples remained unchanged under all these conditions. The Cs leaching rates varied from 7.1 × 10−6 to 1.46 × 10−5 g cm−2 day−1. The “crystal-chemical modeling” of the new possible compositions of the compounds with the expected pollucite structure was performed.