X-ray and electrical conductivity studies in the rubidium selenate tellurate

The new salt Rb2SeO4·Te(OH)6 (RbSeTe) is monoclinic P21/c. The unit cell parameters are: a = 13.783(2) Å, b = 6.791(3) Å, c = 11.713(2) Å, β = 107.23(2)°, Z = 4, V = 1047.0(5) Å3 and ρcal = 3.44 g cm−3. As it was previously described for selenate tellurate, the main feature of this atomic arrangement is the coexistence of two different types of anions (TeO66− and SeO42− groups) in the unit cell, connected by OH⋯O hydrogen bonds which make the building of the crystal. X-ray powder diffraction data confirm that the first anomaly at 430 K can be attributed to a structural phase transition. The conductivity evolution versus temperature shows the presence of a superionic-protonic conduction phase transition at 490 K.