Solvent-free synthesis and stability of MgB12H12

Abstract

MgB₁₂H₁₂ has been widely discussed as an intermediate in the hydrogen sorption cycles of Mg(BH₄)₂, but its properties such as stability and reactivity are still unknown. We achieved the synthesis of MgB₁₂H₁₂via the reaction between Mg(BH₄)₂ and B₂H₆ at 100 to 150 °C. When bulk Mg(BH₄)₂ was used as the starting material, a yield of 10.2 to 22.3 mol% was obtained, which was improved to 92.5 mol% by using Mg(BH₄)₂ nanoparticles. The as-synthesized MgB₁₂H₁₂ decomposed into boron between 400 and 600 °C, preceded by a possible polymerization process. The formation mechanism of MgB₁₂H₁₂ and its role in the decomposition process of Mg(BH₄)₂ are discussed.