Solid-state chemistry continues to play an expanding role in an astounding array of disciplines. As the discovery of new physical phenomena has often depended on the development of new materials, the synthesis of new solid-state materials and kinetically stable composites with optimized properties is of central importance. While solid-state materials have historically been prepared through high temperature solid-state reactions, generally affording the most thermodynamically stable phases, a variety of techniques have been developed to overcome the limitations inherent in this traditional approach.
The solid-state chemistry groups at the University of Oregon have been leaders in the discovery, development, and application of the concept of reaction mechanism to the synthesis of solid-state materials, essentially recruiting for the service of extended solid-state chemistry the basic concepts long used by molecular chemists. D.C. Johnson has developed elementally modulated thin films as reactants and shown how initial film structure controls subsequent reaction pathways. Page has demonstrated the importance of following the evolution of sol-gel samples, particularly for ternary and quaternary systems, as they progress to complex oxides in order to determine processing conditions. Doxsee has pioneered “complexation-mediated crystallization”, controlling the crystallization of both molecular organic solids and extended inorganic solid-state materials through the use of chelating agents in nonaqueous solvents. All of these approaches proceed via amorphous intermediates, allowing the exploitation of nucleation, a kinetic process, as the rate limiting step in the formation of crystalline solids and thereby affording control over the structure of the final solid-state products through the control of nucleation energies.