Formation of an intermediate compound with a B₁₂H₁₂ cluster: Experimental and theoretical studies on magnesium borohydride Mg(BH₄)₂

Experimental and theoretical studies on Mg(BH₄)₂ were carried out from the viewpoint of the formation of the intermediate compound MgB₁₂H₁₂ with B₁₂H₁₂ cluster. The full dehydriding and partial rehydriding reactions of Mg(BH₄) ₂ occurred according to the following multistep reaction: . The dehydriding reaction of Mg(BH₄)₂ starts at approximately 520 K, and 14.4 mass% of hydrogen is released upon heating to 800 K. Furthermore, 6.1 mass% of hydrogen can be rehydrided through the formation of MgB₁₂H₁₂. The mechanism for the formation of MgB ₁₂H₁₂ under the present rehydriding condition is also discussed.