Single-crystal X-ray diffraction data were collected on a Bruker SMART APEX CCDdiffractometer. The single crystals, selected on the basis of their optical properties (regular shape and homogeneity in color) were glued on top of glass capillaries (0.1 mm Ø). Intensity data were collected with graphite-monochromatized Mo Ka X-radiation (50 kV, 30 mA); the crystal-to-detector distance was 30 mm and the detector positioned at -30° and -50° 2Q using an w-scan mode strategy at four different f positions (0°, 90°, 180° and 270°) for each 2Q position. 630 frames with Dw = 0.3° were acquired for each run. With this strategy, data in a large Q-range up to minimum dhkl-values d = 0.53 Å could be acquired. This is necessary for accurate determination of anisotropic displacement parameters and to reduce correlation effects between atomic displacement parameters and site occupation numbers. Three-dimensional data were integrated and corrected for Lorentz-, polarization and background effects using the APEX4 software. Structure solution (using direct methods) and subsequent weighted fullmatrix least-squares refinements on F 2 were done with SHELX-2012 , as implemented in the program suite WinGX 2014. 6H2O was added to each LLZO-p and LLZO-b. Both samples were then dried in air at 120 °C for 6 h after the 57Co probing procedure. Co Mössbauer emission spectra were collected at room temperature with a constant-acceleration spectrometer using a K2MgFe(CN)6 absorber.