Ionic mobility and phase transitions in heptafluorodiantimonates MSb2F7 and Cs(1−x)M x ′Sb2F7 (M′ = K, NH4) according to NMR and DSC data

Ion mobility and phase transitions in heptafluorodiantimonates(III) Cs (1−x) (NH 4 ) x Sb 2 F 7 and K 0.4 Rb 0.6 Sb 2 F 7 according to NMR and DSC data

“…The latter is confirmed by the presence of high ionic conductivity in the sample above 430 K (8 Â 10 À4 S/cm at 433 K). A comparison of experimental data obtained previously for the compounds Cs 1Àx K x Sb 2 F 7 (x 0.6) [16] and the compound K 0.4 Rb 0.6 Sb 2 F 7 studied in this work is of some interest. According to XRD data, structures of the phases Cs 1Àx K x Sb 2 F 7 (x 0.2) and the compound CsSb 2 F 7 (monoclinic symmetry, space group C2/c) are virtually the same.…”

“…A dynamic state of the fluoride sublattice in the compounds Cs (1Àx) K x Sb 2 F 7 is determined by the number of potassium cations introduced into the cesium subsystem [16]. When x < 0.2, in these compounds the higher mobility of fluoride ions is observed at the same conditions as compared to CsSb 2 F 7 , and when x > 0.4, the ion mobility decreases.…”

“…The ion mobility was studied in the compounds K (1Àx) (NH 4 ) x SbF 4 [14], K (1Àx) Cs x SbF 4 [15], and Cs (1Àx) K x Sb 2 F 7 [16]. There is no published data on the character of dynamic processes in the crystalline phases Cs 1Àx (NH 4 ) x Sb 2 F 7 (x = 0.2, 0.6) and K 0.4 Rb 0.6 Sb 2 F 7 .…”