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The new title compound is prepared by solid state reaction of a stoichiometric mixture of CaO2, Os, Fe2O3, and KClO4 (Pt capsule, 6 GPa, 1500 °C, 1 h) and characterized by synchrotron powder XRD, magnetic and electrical resistivity measurements, and DFT calculations.

CaOsO3 and SrOsO3 are synthesized by high-pressure solid state reactions of CaO or SrO and OsO2 (Pt capsule, 6 GPa, 1500—1700 °C, 1 h).

NiS2 hollow spheres are hydrothermally synthesized from a mixture of Ni(NO3)2, L-cysteine, urea, and H2O (autoclave, 140 °C, 24 h).

Oxygen-deficient title compounds with 0 ≤ δ ≤ 0.35 are synthesized from stoichiometric amounts of LaAs, ZnO, and Zn (belt-type high-pressure apparatus, Au capsule, Ar, 6 GPa, 1300 °C, 2 h).

Polycrystalline samples of Sr3Co2-xZnxO6 (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) are synthesized from mixtures of Co, SrO2, and ZnO (6 GPa, 1400 °C, 1 h) and characterized by XRD, electrical resistivity, and magnetic measurements.

The title compound is characterized by neutron diffraction at temperatures between 50 and 295 K.

A postspinel phase of CdRh2O4 is prepared by solid state reaction of a stoichiometric mixture of CdO and Rh2O3 (Au capsule, 6 GPa, 1400 °C, 1 h).

The crystal structure of the title compound is determined by neutron and synchrotron powder diffraction measurements in the temperature range 3—320 K.

Single crystals of the new title compound are prepared by a flux method from mixtures of Ca3OsO6 (obtained from stoichiometric amounts of CaO2 and Os, Pt capsule, 6 GPa, 1500 °C, 1 h), LiCl, and KCl in a mass ratio of 1:5:2 (Pt crucible, 750 °C, 12 h).

Na2OsO4 crystals were grown by a NaCl flux method under high pressure. It crystallizes in the Ca2IrO4-type structure without having additional elements or metal vacancies, which are usually accommodated. It appears that Na2OsO4 is a metal-stoichiometric Ca2IrO4-type compound never been synthesized to date. Na2OsO4 has the octahedral environment of Os6+O6 so that the electronic configuration is 5d2, suggesting the magnetic S=1 ground state. However, magnetization, electrical resistivity, and specific heat measurements indicated that the non-magnetic S=0 state is much likely for Na2OsO4 than the S=1 state. Band structure calculations and the structure analysis found that the disagreement is probably due to the statically uniaxial compression of the OsO6 octahedra, resulting in splitting of the t 2 g band.

While there already exit some routes to prepare carbides, highly efficient and facile routes are still desired to meet the increasing demand on carbides. By a facile solid-state reaction process using graphite-like phase of C3N4 (g-C3N4) as the carbonizing reagent, we synthesized three technologically important carbides including cubic NbC and TaC, and hexagonal WC nanoparticles at relatively low temperature (1150 degrees C). The products were characterized by power X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and high-resolution TEM (HRTEM). The results show that g-C3N4 is a highly efficient carbonizing reagent and the oxides Nb2O5, Ta2O5 and WO3 are completely converted into the corresponding carbides at 1150 degrees C, which is significantly lower than that reported for the commercial preparation of the carbides, typically > 1600 degrees C. The NbC, TaC and WC nanoparticles are found to have an average particle size of 4, 35 and 60 nm, respectively. An important feature of this solid-state reaction process is that g-C3N4 plays double roles as both efficiently reducing and carbonizing reagent. (c) 2006 Elsevier B.V. All rights reserved.