Structure and properties of new crystals in CsHSO₄– CsH₂PO₄– H₂O system

Crystal structure, hydrogen bonds and thermal transformations of superprotonic conductor Cs6(SO4)3(H3PO4)4

“…Optical observations show that the crystals are in an optically isotropic phase under ambient conditions (Fig. 2a), which corresponds to their cubic symmetry with the space group I43d (Makarova, Selezneva et al, 2016). At T $ 370 K, the growth of domains of a new phase and, as a result, the formation of a multiphase state were recorded in the crystals (Fig.…”

“…In order to refine the crystal structure of Cs 6 (SO 4 ) 3 (H 3 PO 4 ) 4 with neutron diffraction data at 290 K, the coordinates of the non-hydrogen atoms of the crystals obtained using synchrotron radiation were taken as the initial data (Makarova, Selezneva et al, 2016). The values of the structural parameters were refined by the full-matrix least-squares method.…”

“…A study of Cs 6 (SO 4 ) 3 (H 3 PO 4 ) 4 crystals by impedance spectroscopy revealed increasing conductivity at a temperature of $370 K and another anomaly at $390 K (Makarova, Selezneva et al, 2016). Compared to other mixed sulfatephosphates of caesium, the behaviour of Cs 6 (SO 4 ) 3 (H 3 PO 4 ) 4 crystals differs substantially; the temperature at which an increase of conductivity appears is lower and high conductivity is observed even after a decrease in temperature.…”

“…To verify the previously obtained data concerning the location of S and P atoms using synchrotron radiation (Makarova, Selezneva et al, 2016), their positions were exchanged. As a result, the refinement of the model with the permutation of the S-and P-atom positions converged to R(F)/wR(F) = 0.0509/0.0807, which clearly indicates a preference for the previous model mentioned above.…”

“…The compound Cs 6 (SO 4 ) 3 (H 3 PO 4 ) 4 was first obtained in the study of various acidic caesium salts of sulfuric and phosphoric acids (Komornikov et al, 2016;Makarova, Selezneva et al, 2016). When studying the composition of this compound, it was found that Cs 6 (SO 4 ) 3 -(H 3 PO 4 ) 4 crystallizes from the CsOH-H 2 SO 4 -H 3 PO 4 -H 2 O four-component system.…”