Cesium and Cesium-Lithium Selenates

Abstract

The Cs2SeO4-H2SeO4-H2O and Cs2SeO4-Li2SeO4-H2O systems were studied at 30 °C as a basis for determining the conditions for formation of the compound Cs4LiH3(SeO4)4, which has been observed to undergo a ferroelectric phase transition. The results of a solubility study were used to construct a pseudo-ternary cross-section for CsLiSeO4-CsHSeO4-H2O in the quaternary system Cs2SeO4-Li2SeO4-H2SeO4-H2O, which demonstrated that, in the region of crystallization of the compound of interest, a substance with the composition Cs4LiH3(SeO4)4 is actually formed. Attention was further paid to the following newly prepared compounds: cesium-lithium selenate hemihydrate, CsLiSeO4·1/2 H2O, tricesium-lithium bis(selenate) hemihydrate, Cs3Li(SeO4)2·1/2 H2O and hydrogen tricesium bis(selenate) hemihydrate, Cs3H(SeO4)2·1/2 H2O, which were characterized by X-ray, spectral and thermoanalytical data.