Preparation and crystal structures of novel LaOAgS-type copper and silver fluoride chalcogenides

Systematic studies of LaOAgS-type alkaline earth–Cu/Ag fluoride chalcogenides revealed six new compounds SrFCuTe, SrFAgS, SrFAgSe, SrFAgTe, BaFAgS, and BaFAgSe. Crystal structures have been determined for these as well as for BaFCuS. Based on trends in the bond distances within the PbO- and FeS-type layers, a semi-qualitative approach is suggested to predict new members of the LaOAgS family.

► Six new alkaline earth–coinage metal fluoride chalcogenides were prepared.
► All new compounds adopt the LaOAgS structure type.
► Bond distances in their structures are transferable within 2–3%.
► The hardness of fluorite slabs towards deformations strongly affects stability of LaOAgS-type compounds containing large anions at the S site.