Possibility Landscapes of Chemistry

Possibility Landscapes of Chemistry is a public research series examining chemical systems in which composition alone does not determine a unique structure or state. The series develops domain-specific, set-valued frameworks for classifying chemically and structurally admissible sectors under predefined boundary conditions and bounded uncertainty. The first two papers address oxygen-vacancy ordering in nonstoichiometric ceria and vacancy–interstitial defect clustering in wüstite. In both cases, the approach distinguishes structural admissibility from thermodynamic preference, kinetic accessibility, and experimental prevalence. Possible outcomes are classified as excluded, possible, robust, or unresolved. The series is intended to complement established methods in defect chemistry, materials modelling, electronic-structure theory, and experimental structure determination. It does not provide inverse-design procedures, synthesis instructions, or a universal replacement for existing chemical theories.