4. Conclusion

molecule (H2O) [23] may be an indication of the presence of strong hydrogen bonding in the new crystal. The external modes of the HSeO3 ion, lattice modes of water, and metal-oxygen

Figure 8 shows an illustration of the temperature dependence of the dielectric constant (ε<sup>0</sup>

the frequency range [1–10] KHz, and in the temperature region of 300–500 K obtained for [Cu0.335Se0.582(HSeO3)2CuCl3(H2O)3]. These curves (Figure 8) exhibit the following character-

(1) There is one anomaly in the dielectric constant ε<sup>0</sup> observed at about 383 K, (2) there is a maxima in the permittivity curves, displaced to higher temperatures with increasing frequency, and (3) apparently, this is a transition which can be attributed to the "order-disorder" phase transition, probably characterizing the motion of H+ diffusion related to the motion of

[1].

) in

stretching modes appear approximately below 200 cm�<sup>l</sup>

HSeO3 groups, as reported in the literature [16, 17].

Figure 8. Temperature dependence of ε' as a function of frequency.

3.3. Dielectric studies

40 Chalcogen Chemistry

istics:

In conclusion, the author ascertains that a novel substituted hydrogen selenites [Cu0.335Se0.582 (HSeO3)2CuCl3(H2O)3], have been successfully prepared via slow evaporation method. The crystal structure of the novel compound is characterized by the presence of structural blocs with structures as such [Cu0.335Se0.582(HSeO3)2] and [CuCl3(H2O)3]. The principal compound is arranged to form layers in the structure parallel to the (001) plane between which the lone pairs E are located. So, the main feature of the structure of this compound is based on different coordination polyhedral, SeO3 pyramids, and [CuCl3(H2O)3] groups. The presence of hydrogen selenites (SedOdH) was confirmed by IR and Raman spectra. The particularity of [Cu0.335Se0.582(HSeO3)2CuCl3(H2O)3] is that it undergoes a phase transition on heating at 383 K. High temperature structure investigation of the new compound is in our future plans in order to confirm the nature of this transformation.
