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Boron nitride hollow spheres were synthesized by the reaction of BBr3 and NaNH2 at room temperature; X-ray powder diffraction pattern could be indexed as hexagonal BN with the lattice constants of a=2.482 and c=6.701 A˚; high-resolution transmission electron microscopy image showed the hollow spheres consisted of BN nanoparticles, with diameter between 80 and 300 nm; a possible formation mechanism of BN hollow spheres was discussed. [Copyright &y& Elsevier]

Mn5Si3 nanocages and nanotubes were successfully synthesized by molten salt flux reaction at 650 °C. The samples were characterized with X-ray powder diffraction and transmission electron microscopy. The influence of the reactants molar ratio of MnCl2 to Mg2Si and reaction temperature on the phases and morphologies of the products were discussed. The possible mechanism of forming Mn5Si3 nanocages and nanotubes is discussed. [Copyright &y& Elsevier]

Nanocrystalline titanium diboride (TiB2) has been prepared by the reaction of TiCl4 with NaBH4 in the temperature range of 500–700 °C in an autoclave. X-ray powder diffraction (XRD) patterns can be indexed as hexagonal TiB2 with the lattice constants of a=3.032 and c=3.229 A˚. Transmission electron microscopy (TEM) image shows particle morphology, with average size of 15 nm for the powder obtained at 600 °C. Selected area electron diffraction (SAED) pattern confirms the prepared hexagonal TiB2. The oxidation behavior of TiB2 is studied by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). [Copyright &y& Elsevier]

Molybdenum carbide (Mo2C) has been synthesized via a sodium co-reduction of molybdenum pentachloride (MoCl5) and carbon tetrabromide (CBr4) in benzene at 350 °C for 12 h. X-ray diffraction (XRD) pattern indicated that the product was mainly hexagonal Mo2C with a small amount of cubic Mo2C. The lattice constants of the hexagonal Mo2C were a=3.009 and c=4.736 A˚. Transmission electron microscopy (TEM) study showed that the product consisted of slightly conglomerated particles of about 30 nm in size. [Copyright &y& Elsevier]

Nanocrystalline titanium diboride (TiB2) has been prepared through a reduction–boronation route by using Ti powders and BBr3 as titanium and boron sources, and metallic sodium as reductant at 400 °C. X-ray powder diffraction (XRD) pattern can be indexed as hexagonal TiB2 with the lattice constants of a=3.028 and c=3.223 A˚. Transmission electron microscopy images show particle morphology with average size of 15 nm. Selected area electron diffraction patterns confirm the preparation of the hexagonal TiB2. [Copyright &y& Elsevier]

B4C ultrafine powders were successfully synthesized at 450 °C through a new co-reduction route. The synthesis was carried out in an autoclave by using BBr3 and CCl4 as the reactants and metallic Na as the co-reductant. The X-ray powder diffraction pattern and Raman spectra indicate the formation of B4C. An atomic ratio of B to C of 4.09:1.0 was determined from X-ray photoelectron spectra. Transmission electron microscopy images shows that typical B4C crystallites are composed of uniform ultrafine spherical and rod-like particles. [Copyright &y& Elsevier]