Abstract

Different Synthetic Routes of Group Six (VIB) Nano-Metal Borides

Omar Ali Al-Zain and Al-Masoudi RS

For the first time, the synthetic comparison between the solid and liquid phases of metal borides was subjected to empirical investigation. The magnesiothermic reaction of CrO3, B2O3, and Mg yielded the only C2rO3. Similarly, the direct reaction of CrO3 or CrCl3 with elemental boron yielded chromium oxides. On the other hand, direct reaction of pure Cr metal with elemental boron in 1:1, 1:2 and 1:3 ratios, showed that only 1:3 ratio, produced a mixture of Cr2B, Cr2O3, and CrO3 (minimal oxides). Going down group six, (VIB) MoO3 and WO3, reacted directly with elemental boron in a muffle furnace at 500, 700 and 1000°C for 2, 2 and 15 hours respectively, yielding black beautiful nanocrystals of Mo2B4, MoB, WB4, and W2B5. The liquid phase reaction of molybdenum pentachloride, MoCl5, with sodium borohydride, NaBH4 (1:5 ratio), produced black nanocrystals and nanorods of MoB and MoB4. Reacting chromium trichloride with sodium borohydride, NaBH4 (1:3 ratio), in solution, produced pure black nanocrystals and nanorods of Cr2B, while the reaction of chromium dichloride with sodium borohydride, NaBH4 (1:2 ratio), in solution, produced a mixture of Cr2B and Cr2O3.