Structure Topology in Silver(I)-(poly)chalcogenide Halides: A Helpful Tool to Understand Structure Relations and Properties

Recent progress in the field of silver(I)-chalcogenide halides and silver(I)-polychalcogenide halides led to the discovery of a reasonable number of new phases, solid Solutions and even a new substance class of materials with favorable electronic and thermoelectric properties. Most of these new compounds are characterized by a pronounced ion mobility, polymorphism, and complex structures, which result ill severe problems during the structure solution, the refinement, and even the description of the crystal structures. Herein we report oil a very simple but effective building principle and a topological structure approach, which are both based oil the separate description of anion substructures and the introduction of discrete building blocks. Such a topological principle helps to understand the complex structural relations and allows one to discuss all known chalcogenide and polychalcogenide halides in a Continuous sequence of compounds. Following this principle it is possible to understand physical properties and to predict new phases in the system.