Discovery of Layered Indium Hydroxide via a Hydroperoxyl Anion Coordinated Precursor at Room Temperature

All reported layered metal hydroxides have brucite-like metal-hydroxyl host layers, and the discovery of other types of layered metal hydroxides could significantly extend the layered metal hydroxide families, which is meaningful in both theory and applications. Here, through hydroperoxyl anion coordinated In³⁺ cations as a precursor, a new layered indium hydroxide was synthesized, where only a three-dimensional cubic phase had existed before. The layer of the product exhibits an unusual structure where In(OH)₆ octahedra share edges and vertexes with each other to form layers, which is completely different from the common edge-sharing brucite-like metal-hydroxyl layers. By investigating the formation mechanism, the new layered structure is found to be formed by changing the traditional crystallization path through the hydroperoxyl anion coordinated intermediates. Many other new phases could also be discovered by following the same intrinsic principle.