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Alkali borohydrides MBH 4 and their deuterides have been investigated by X-ray and neutron powder diffraction (M = K, Rb, Cs) and by infrared and Raman spectroscopy (M = Na, K, Rb, Cs). At room temperature the compounds crystallize with a cubic high temperature (HT) structure having Fm3m symmetry in which the [BH 4 ] − complexes are disordered. At low temperature (LT) the potassium compound transforms into a tetragonal low temperature structure having P4 2 /n mc symmetry in which the [BH 4 ] − complexes are ordered such as in the isotypic sodium congener. The B-H distances within the complex as measured on the deuteride at 1.5 K are 1.205(3) Å. Indications for a partial ordering in the rubidium and cesium compounds exist but are not sufficient for a full structural characterization. Infrared and Raman spectra at room temperature are fully assigned for both hydrides and deuterides, including the overtones and combination bands, the Fermi resonance type interactions and the 10 B to 11 B splitting due to the presence of natural boron in the samples.

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International audienceHybrid materials based on layered double hydroxides (LDHs) exhibit great potential in diverse fields such as health care, polymer composites, environment, catalysis, and energy generation. Indeed, the compositional flexibility and the scalability of LDH structures, their low cost, and their ease of synthesis have made hybrid LDHs extremely attractive for constructing smart and high-performance multifunctional materials. This review provides a comprehensive and critical overview of the current research on multifunctional hybrid LDHs. Organic–inorganic hybrid LDHs, intercalated and surface-immobilized structures, are both specifically addressed. The new trends and strategies for hybrid LDH synthesis are first described, and then the potential of the latest hybrid LDHs, polymer LDH nanocomposites, and LDH bio-nanocomposites are presented. Significant achievements published from ≈2010, including authors' results, which employ hybrid LDH assemblies in materials science, medicine, polymer nanocomposites, cement chemistry, and environmental technologies, are specifically addressed. It is concluded with remarks on present challenges and future prospects

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Metal-organic frameworks (MOFs) and particularly their subclass - Zeolite Imidazolate Frameworks (ZIFs) - are used for a variety of applications including particularly energy storage. Highly porous MOFs mixed with non-wetting liquids can be used to form molecular springs (MS) for efficient mechanical and thermal energy storage/transformation. In this paper by means of high-pressure calorimetry the energetic characteristics of {ZIF-8 + water} MS were investigated in wide temperature and pressure ranges. Unexpectedly XRD measurements show that the concomitant effects of temperature and pressure on {ZIF-8 + water} MS leads to an irreversible change of the ZIF-8 structure, transforming its symmetry from cubic to orthorhombic. Whereas, previous studies have demonstrated the stability of ZIF-8 under either high pressure or high temperature.

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