Dear Kanimozhi S.N ,

By the metal it self no.

Nevertheless, metals have different electron densities, and therefore volumes. Changing significant metal volume by lesser one's or inversely will induce dislocations, that would reflect in the XRD pattern. Other visible effects are the ability of different metals bond or interlayer them self's in significant different ways, different interaction sites, or surrounding environments inside the layered double hydroxides. All those effects among others will induce characteristic changes in the XRD patterns, not to mention here the lattice size variety obtained by long-range arrangement usually achieved by the natural lower system energy final configuration.

In case of very small change not inducing significantly the final energy configuration the patterns will be quite similar.

Finally, the DLH framework in isolated point of view, has a characteristic XRD pattern, that by energy minimization movements will reflect the real final configuration, depending on the metal characteristic used in the synthesis or interlayer promoted change.

Best regards

WNM

Dear Kanimozhi S.N ,

LDHs are a very complex issue and it is difficult to summarize. Based on the natural phases, a classification system of the hydrotalcite supergroup was developed (Mills et al, 2012), which is also applicable to synthetic LDHs. The term hydrotalcite supergroup is in mineralogy equivalent to the term LDHs. The phases are divided into eight groups based on crystal structures (+ some unclassified). The differences of the lattice parameters (and thus in PXRD) within the individual groups are only very small, the space group is the same even though Me (II) and Me (III) are different.

The answer to the question of whether layered double hydroxides have a characteristic XRD pattern, regardless of the metal used, seems to be the answer - yes, but there are at least 8 of these patterns and many of them have additional polytype modifications.

https://www.researchgate.net/publication/260165139_Nomenclature_of_the_hydrotalcite_supergroup_Natural_layered_double_hydroxides