{"knowledge_schema": {"broad_category": "Chemistry \u2192 Materials Science \u2192 Perovskite Structures", "refinement": "This topic focuses on the organic cations that can occupy the A-site in lead halide perovskites, which are crucial for the stability and properties of these materials.", "specific_scope": "The inquiry is specifically about organic A-site cations that can independently form three-dimensional structures with lead halides, such as A-Pb-Br3.", "goal": "Identify and list all possible organic A-site cations that can form stable three-dimensional lead halide perovskite structures."}, "summary": "The question pertains to identifying organic A-site cations that can form three-dimensional lead halide perovskite structures, specifically A-Pb-Br3. The focus is on organic cations that can independently stabilize these structures. The candidates provided include various combinations of cations such as Cesium, Methylammonium, Formamidinium, and others. The goal is to determine which of these combinations are valid for forming stable perovskite structures."}