Rapid solid-state transformation of tetrahedral [AlH4]− into octahedral [AlH6]3− in lithium aluminohydride

Abstract

Polycrystalline LiAlH₄ transforms into polycrystalline Li₃AlH₆ and Al during short time (5 min) ball-milling with 3 mol% TiCl₄ at room temperature; solid-state rearrangement of tetrahedral [AlH₄]⁻ into octahedral [AlH₆]³⁻ at ambient conditions was previously unknown; this transformation does not occur during ball-milling of pure LiAlH₄ or in the presence of 3 mol% TiCl₄ without mechanochemical treatment.