Optical electronegativities, lead compounds

Parameters of the three-dimensional structures function as operators between the properties of elements on the one hand, e.g., electronic structure, electronegativity, atomic radii, and properties of the compounds on the other hand, e.g., chemical reactivity, hardness, elasticity, ferroelectricity, electrical conductivity, optical rotatory power, refraction. Mathematical procedures lead from the elements to the structures and from the structures to the properties. If these are formulated as computer programs, they need data given in databases. If databases are used in this way, existing theories cannot only be demonstrated for individual examples but also verified as generally true. 

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