A layered double hydroxide (LDH) with nitrate as the counter anion (LDH-NO 3 with Mg/Al = 3) was, for the first time, successfully delaminated in formamide under ultrasonic treatment. Atomic force microscopy (AFM) images showed that a large part of the LDH was delaminated into single and double brucite layers (0.7-1.4 nm in thickness). The nano-sheets had disk-like shapes with a diameter of ca. 20-40 nm. Findings from AFM were in good agreement with the average hydrodynamic diameter determined using dynamic light scattering. Powder X-ray diffraction pattern of LDH dispersed in formamide also confirmed that LDH-NO 3 was exfoliated. The dispersions of LDH in formamide were stable and transparent up to a concentration of 40 g L 21 . However, formation of transparent gels was observed at concentrations higher than 5 g L 21 . Delaminated LDH could be restacked by adding sodium carbonate or ethanol.

SAPO-34 (SAPO:  silicoaluminophosphate) has been synthesized and examined by in situ multinuclear high-resolution NMR under hydrothermal conditions (170 °C) in the presence of HF, using morpholine as the structure-directing agent. Four routes have been examined:  (a) from a SAPO gel with HF (triclinic SAPO-34), (b) from a SAPO gel without HF (trigonal SAPO-34), (c) from an AlPO4 gel with HF (triclinic AlPO4-34), and (d) from a slurry containing the layered AlPO4F prephase (triclinic AlPO4-34). In situ 13C, 19F, 27Al, and 31P NMR have uncovered the main steps of the reaction. The gel dissolves into small units condensed to no more than 4-rings (4R). The next steps are formation of a layered intermediate (the prephase), redissolution of the prephase into 4R building units of different types depending on the fluoride contents and aluminum coordination, and the subsequent nucleation and crystallization of triclinic AlPO4/SAPO-34. The initial fast process leads to the formation of the prephase made of an alternating stacking of 4R type-II units. When approaching 170 °C, this phase redissolves in 4R type-III units with aluminum in five-coordination. With additional defluorination, 4R type-IV units transform into 4R type-V units and both types connect in a chabazite topology. One 4R type-IV unit clips two fluorine atoms into the bridging position in the 4-ring and subsequently shapes the network topology into its crystalline order. The mechanism provided can now be subjected to further chemical testing for purposes of syntheses optimization.

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