Powder XRD data were obtained on small batches of microcrystalline 1-M that were suspended in Fomblin ® oil to prevent sample decomposition from oxygen and water. These samples were mounted on a Micromount TM and placed on a goniometer head under a cryostream to cool the sample to 100 K, the Fomblin ® to suspend the crystallites for the duration of the experiment. The PXRD data were measured on a Rigaku FR-X diffractometer, operating in powder diffraction mode using Cu Kα radiation (λ = 1.5418 Å) with a Hypix-6000HE detector and an Oxford Cryosystems nitrogen flow gas system. Data were collected between 3-20 °θ, with a detector distance of 150 mm and a beam divergence of 1.5 mRad. X-ray data were collected using CrysAlisPro. For data processing the instrument was calibrated using silver behenate as standard. Then, X-ray data were reduced and integrated using CrysAlisPro. Pawley refinements with the unit cells obtained from the crystal structures were performed using TOPAS. X-ray diffraction data for single crystals of 1-La, 1-Ce, 1-Pr, 1-Nd and 1-U in Fomblin ® on a Micromount TM were examined using a Rigaku FR-X diffractometer, equipped with a HyPix 6000HE photon counting pixel array detector with graphite-monochromated Mo Kα (λ = 0.71073 Å) (1-U) or Cu Kα (λ = 1.5418 Å) (1-La, 1-Ce, 1-Pr, 1-Nd) radiation. Intensities were integrated from data recorded on 1° frames by ω rotation. Cell parameters were refined from the observed positions of all strong reflections in each data set. A Gaussian grid face-indexed with a beam profile was applied for all structures. The structures were solved using SHELXT; in Bruker TopSpin v4.0.9. All ssNMR spectra were referenced to TMS ( 1 H and 29 Si). Experiments were acquired at ambient temperature using various MAS frequencies. For the frequencies employed (5 to 12 kHz), the sample temperature was determined using an external reference of KBr to be 301 ± 10 K.