Room-temperature synthesis of nickel borides via decomposition of NaBH(4) promoted by nickel bromide.

Riccarda Caputo, Fabrizio Guzzetta, Alexander Angerhofer

Index: Inorg. Chem. 49(19) , 8756-62, (2010)

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Abstract

We report the formation of nickel borides, at room temperature and pressure, from the decomposition of NaBH(4) promoted by the addition of nickel bromide at different concentrations in a dispersing organic medium, tetrahydrofuran and pentane. The nickel borides, formed as amorphous powders, were analyzed, and the structure information served as input for modeling a periodic lattice structure with the same composition. Experimentally, the nickel boride phases were predominantly composed of a boron-rich phase with composition NiB(3). Combining FT-IR, X-ray diffraction analyses, and theoretical structure determination, we suggest for it a monoclinic structure, with symmetry group P2(1)/c, lattice parameters a =3.038 Å, b = 8.220 Å, c = 5.212 Å, α = β = 90.00° and γ = 87.57°. The enthalpies of formation of the nickel boride phases, as well as the lattice stability, were calculated using density functional theory and density functional perturbation theory methods.