Biomedical subjects
Publications and source records attributed to Claude Belin.
The crystal structure of the title compound, C18H23N5O.H2O, shows molecules containing a phenol group linked perpendicularly to a roughly planar fragment comprising two pyrazole rings. Molecules are stacked perpendicular to the [101] direction, with their phenol groups disposed alternately. The molecular packing in the crystal is stabilized by hydrogen bonding involving water molecules.
Nonhydrolytic sol-gel processes in organic solvents have become very popular for the synthesis of metal oxide NCs. We report an affordable, high-yield, shape-control synthesis of MnO multipod nanocrystals with a quick reaction time. The reaction yields exclusively multipods; two to six pod nanocrystals are synthesized. The mechanism leading to this hierarchical nanostructure is studied in relation with an oriented attachment mechanism; all nanocrystals are found to be single crystals. The study is completed by high-resolution TEM, X-ray powder diffraction, and magnetic measurements.
Single crystals of pentasamarium trigallium, Sm5Ga3, display tetragonal symmetry. The crystal structure was solved and refined in space group P4/ncc. The present work does not confirm the space group I4/mcm previously deduced from powder data measurements. One Sm atom is in a general position, and the other Sm atom and one of the Ga atoms are at sites with fourfold symmetry. The remaining Ga atom is at a site with twofold symmetry.
Aluminium germanium lithium, AlGeLi, crystallizes in two cubic dimorphs. The structure of the F-43m form, already inferred from powder data, has been confirmed by both powder and single-crystal X-ray diffraction studies. The second dimorph, not previously identified, adopts a disordered centrosymmetric structure with space group Fm-3m.
The title compound, lithium aluminium silicide (15/3/6), crystallizes in the hexagonal centrosymmetric space group P6(3)/m. The three-dimensional structure of this ternary compound may be depicted as two interpenetrating lattices, namely a graphite-like Li(3)Al(3)Si(6) layer and a distorted diamond-like lithium lattice. As is commonly found for LiAl alloys, the Li and Al atoms are found to share some crystallographic sites. The diamond-like lattice is built up of Li cations, and the graphite-like anionic layer is composed of Si, Al and Li atoms in which Si and Al are covalently bonded [Si-Al = 2.4672 (4) A].
The structure of the alpha-(Al,Si)CuFe approximant phase is determined by a single-crystal X-ray diffraction study and compared to the ideal structure obtained by the perpendicular shear method of the parent icosahedral phase. It is shown that the local environments (typical atomic clusters) of the two phases are similar and expand significantly farther than the size of the unit cell of the approximant. The orbit Al(2) issuing from the theoretical icosahedral model corresponding to the inner dodecahedron of the Mackay-type cluster is not found in the approximant and is replaced by a partially occupied inner icosahedron with an unusually large Debye-Waller factor.