ESR LINE SHAPE STUDY IN THE INCOMMENSURATE PHASE OF K2SeO4 and RbH3(SeO3)2 CRYSTALS.

The temperature dependence of ESR spectra for K//2SeO//4 doped with VO**2** plus and RbH//3(SeO//3)//2 with Cr**3** plus has been studied in the incommensurate phases. The experimental line shape for RbH//3(SeO//3)//2 near T//C can be well expressed by the same model proposed for the incommensurate phase in K//2SeO//4. This fact indicates that the crystal RbH//3(SeO//3)//2 containing Cr**3** plus has an incommensurate phase in the temperature range between about 150 and 160 K.