Within the framework of this topic, we are interested in the reactivity of lamellar matrices containing oligomers (Qn)^2- (Q = S, Se; n = 2-4) towards a metal.The reactivity of precursor La₂O₂S₂ perfectly sums up our research theme.This compound, constructed from ²/∞[La₂O₂]²⁺ sheets separated by free pairs (S₂)^2-, can intercalate Cu at low temperature to lead to the compound La₂O₂Cu₂S₂.During this reaction, the sulfur pair (S₂)^2- is reduced by copper according to the reaction (S₂)^2- + 2 Cu° → 2 S^2- + 2 Cu⁺. This reaction is reversible, the Cu atoms being able to be removed from La₂O₂Cu₂S₂ at 200 °C with I₂ as oxidant.We have shown that similar reactions can be obtained using other polychalcogenides (BaS₃, LaSe₂...) or other transition elements (Fe, Co, Ni).We are currently exploring the reactivity towards alkali metals.

To go further : [Chalcogen Dimers], [Oligomers]