Compositional evolution of the NaZn structure motif in the systems La-Ni-Ga and Ce-Ni-Ga.

Phase relationship and structural behaviour in the substitutional series LaNiGa and CeNiGa have been studied by a combination of X-ray powder diffraction measurements, differential scanning calorimetry, electron diffraction tomography and metallographic analyses. The sequence of morphotropic phase transformations has been found in the series LaNiGa resulting in five varieties of the NaZn structure: the cubic phase with aristotype structure at x = 2 (space group Fm3[combining macron]c, Pearson symbol cF112), two tetragonal phases at x = 2.5-4.

Reversible adsorption of nitrogen dioxide within a robust porous metal-organic framework.

Nitrogen dioxide (NO) is a major air pollutant causing significant environmental and health problems. We report reversible adsorption of NO in a robust metal-organic framework. Under ambient conditions, MFM-300(Al) exhibits a reversible NO isotherm uptake of 14.

Synthesis, crystallization, X-ray structural characterization and solid-state assembly of a cyclic hexapeptoid with propargyl and methoxyethyl side chains.

The synthesis and the structural characterization of a cyclic hexapeptoid with four methoxyethyl and two propargyl side chains have disclosed the presence of a hydrate crystal form [form (I)] and an anhydrous crystal form [form (II)]. The relative amounts of form (I) and form (II) in the as-purified product were determined by Rietveld refinement and depend on the purification procedures. In crystal form (I), peptoid molecules assemble in a columnar arrangement by means of side-chain-to-backbone C=CH.

Structure and magnetic property of potassium intercalated pentacene: observation of superconducting phase in K CH.

We report the results from systematic investigations on the structure and magnetic properties of potassium intercalated pentacene as a function of potassium content, K CH (1  ⩽  x  ⩽  3). Synchrotron radiation powder x-ray diffraction technique revealed that there are two different stable phases can be obtained via potassium intercalation, namely, KCH phase and KCH phase. Structural phase transition was induced when the potassium content was increased to the nominal value x  =  3.

Distribution of Al atoms in the clathrate-I phase Ba8AlxSi46-x at x = 6.9.

The clathrate-I phase Ba8AlxSi46-x has been structurally characterized at the composition x = 6.9 (space group Pm3[combining macron]n, no. 223, a = 10.

Perovskite to postperovskite transition in NaFeF3.

The GdFeO3-type perovskite NaFeF3 transforms to CaIrO3-type postperovskite at pressures as low as 9 GPa at room temperature. The details of such a transition were investigated by in situ synchrotron powder diffraction in a multianvil press. Fit of the p-V data showed that the perovskite phase is more compressible than related chemistries with a strongly anisotropic response of the lattice metrics to increasing pressure.

Bio-inspired band gap engineering of zinc oxide by intracrystalline incorporation of amino acids.

Bandgap engineering of zinc oxide semiconductors can be achieved using a bio-inspired method. During a bioInspired crystallization process, incorporation of amino acids into the crystal structure of ZnO induces lattice strain that leads to linear bandgap shifts. This allows for fine tuning of the bandgap in a bio-inspired route.

Pressure effects in the isoelectronic REFe0.85Ir0.15AsO system.

The effect of chemical and hydrostatic pressure has been studied systematically in a selected system belonging to the 1111 family of iron pnictide high-temperature superconductors. The results show a surprising similarity between the trend of critical temperature vs hydrostatic pressure for isoelectronic samples with different rare earths (RE) on the RE site and samples of the SmFeAsO(1-x)F(x) series with different doping levels. These results open new questions about the underlying mechanism for superconductivity in iron pnictides.