Structures and phase transition of β- and γ-Ag₃IS

Crystal Chemistry of Perovskite-Type Hydride NaMgH3: Implications for Hydrogen Storage

“…Therefore, the impact of structural changes on the activation energy is a significant driver for the increased hydrogen migration rate observed in NaMgH 3 at high temperature. NaMgH 3 maintains a perovskite structure over the temperature range studied (up to 370 K), and we did not observe any structure variation such as a phase transition to a superionic phase with higher symmetry, 42 or any Na/Mg cation-site disordering. Therefore, the reduced tilt angle and lattice distortion with temperature is consistent with the observed increased hydrogen mobility in NaMgH 3 at high temperatures.…”

NMR Studies of the Hydrogen Storage Compound NaMgH3

“…This specifically rules out liquidlike (10 11 -10 12 s -1 ) hopping rates and the fast motion rates typical of superionic conducting solids. 20,21 In Figure 5, the weak temperature dependence of T 2 * toward lower temperatures reflects our selection of the narrow component of the resonance.…”

Crystal Structures of Fast Ion Conductors

“…The main minimum is elearly displaced from the face center to x � 0.4. This is just the position that the Ag ions occupy in the f1 phase and in the y phase (35,37,(39)(40)(41). [The I and S ions form an ordered framework in the simple cubic f1 phase, which exists between 155 and 515 K. In the low temperature trigonal y phase, the Ag ions order, too (37,41).…”