Abstract 9612148 Hwu The aim of this research is to explore a new class of extended solids that contain nanosize, transition-metal-oxide frameworks and to investigate the behavior of the delocalized electrons of oxide-bridged, transition-metal (TM) magnetic centers in a confined lattice. The anticipated structures consist of TM-oxide chains (wires), layers (sheets) and oligomers (dots) that are structurally separated and electronically isolated by closed-shell, non-magnetic oxyanions, i.e., silicates, phosphates and arsenates. Efforts in exploratory synthesis will focus on (1) homologous series containing sheets and wires of rutile and perovskite frameworks and (2) silicate compounds containing nanosize frameworks of late TM oxides. Molten-salt methods, using alkali and/or alkaline-earth metal halides, will be employed, since it is a proven technique for the crystal growth of these refractory oxides. Compound characterizations will be directed toward understanding the bond strength, spin-spin and spin-lattice interactions, band structures, and the onset of metallic properties associated with finite TM-oxide structures. This proposed research is significant because the anticipated TM-oxide fragments with different lengths and geometries will provide a library of structural models for studying the behavior of the delocalized electrons in a confined space. Also, compounds containing TM-oxide frameworks with finite structures may possess novel electronic and/or magnetic properties, which are incompatible with the properties of extended oxides and will be of both scientific and technological interest. Finally, the research outlined in this proposal will provide invaluable fundamental knowledge necessary to continue advancing technology for materials that are of electronic and magnetic importance. %%% Recent advances in technology and the need for new materials in device applications have driven the rapid growth of solid-state science. Understanding fundamen tal parameters that govern the performance of a material has played a crucial role in every area of this multi-disciplinary science, which includes solid-state chemistry and physics, as well as interdisciplinary areas such as electrical and materials science engineering. Solid-state chemistry is concerned with the synthesis of materials with extended structures and their related properties. The variety and complexity of these solids' structures, and the evaluation of the factors that influence and control structural and physical properties, are the elements that have made solid-state chemistry a dynamic area of study. As a result, attempts to modify known structures and explore new ones with novel properties are made with the aim of revealing parameters that may be used to fine tune the physical properties and to ultimately synthesize the desired materials. Currently, the ability to predict the composition and structure for extended solids is not yet possible and synthetic discoveries that have led to landmark advances in solid-state science have nearly always been made through exploratory synthesis, rather than by design. The research outlined in this proposal will provide invaluable fundamental knowledge necessary to continue advancing technology for materials that are of electronic and magnetic importance. The aim is to explore new class of extended solids that contain nanosize, transition-metal-oxide frameworks.
