Abstract
The mixed crystals of RbHSeO4-RbHSO4 have been grown and their properties have been investigated. Dielectric, DTA and X-ray studies allowed us to construct the phase diagram of the system with molar fraction, x, of RbHSO4 as a parameter. It has been found that the crystals with 0.65 ≤ x < 0.8 show some frustrated character. No mixed crystals were found to exist for 0.22 < x < 0.65.