Polymorphic Molecular Materials—The Importance of Tertiary Structures

Molecule-based materials can exhibit a variety of technologically useful cooperative properties not associated with individual molecules, such as ferromagnetism, superconductivity, and ferroelectricity. Selected examples are used to illustrate the fact that, although in general the molecular structure differs in only minor ways, the qualitative or quantitative differences of the crystal or tertiary structure may lead to substantial differences in the solid-state bulk (magnetic) properties, e.g., presence or lack of ordering, or simply a raising or lowering of the ordering temperature.