Structural Synthon Approach to the Study of Stacking Faults in the Layered Double Hydroxides of Lithium and Aluminum

A single layer of the Li-Al layered double hydroxide (LDH) can be considered to be a structural synthon that can be stacked in a number of ways to give rise to the polytypes of the Li-Al LDH family. The topotactic imbibition of lithium into gibbsite and bayerite precursors gives rise to crystalline 2H and 1M1 polytypes respectively. In contrast the sample formed through a gel to crystallite route is found to be a 1M1 polytype with stacking disorders whose local symmetry corresponds to the 1M2 polytype. On heating, a solid-solid 1M1?1H polytype transformation is observed.