THE STUDY OF CSI-EUI2 BINARY-SYSTEM

The CsI-EuI2 system has been studied by differential thermal analysis and Xray powder diffraction Guinier techniques. The phase diagram belo ng to eutectic type with three componunds. The CsEuI3 and Cs3EuI5 are congruent compounds, their melting points are 915K and 814K respectifl y, the CsEu2I5 is one incongruent compound, peritectic point is 744K. There are two eutectic species, their eutectic points occur at 738K an d 804K with 14.3mol% CsI and 72.5mol% CsI. The crystal structural inve stigation of Cs3EuI5 show that it is hexagonal system: a = 1.4634(4)nm , c = 1.8376(0)nm, D-c 4.619g . cm(-3), D-m(298) = 4.549g . cm(-3). Th e valence of europinum in Cs3EuI5 has been determined by magnetic susc eplibility, XPS and fluorescence spectry.