Dr. Peter K. Dorhout, Department of Chemistry, Colorado State University, is supported by the Inorganic, Bioinorganic, and Organometallic Program of the Chemistry Division under a Faculty Early Career Development Award for studies of the use of Zintl ion building blocks in material synthesis. Lanthanide Zintl ion materials will be synthesized using a building block concept whereby known Zintl phase structures are examined as precursors to and reactants for new materials. New lanthanide selenodiphosphate and selenoantimonate compounds will be prepared from molten salt reactions at moderate temperatures. These materials are expected to show thermoelectric and/or antiferromagnetic behavior, and these properties and their theoretical basis will be examined. The educational plan is aimed at developing new laboratory experiments in X-ray diffraction and thermal analysis, a new course in solid state chemistry, and an undergraduate research program. Unique combinations of elements from various portions of the periodic table can result in solid state materials with new and useful properties. The synthesis of these types of materials is frequently approached in an empirical, trial-and-error fashion by combining the elements at high temperature. This proposal combines Zintl ions, negatively charged clusters of main group elements, with lanthanide metals in a systematic and rational building block approach. This approach is aimed at developing low temperature synthetic routes to these materials, and a fundamental understanding of the basis for the observed physical properties of these materials. These materials may posess unique conducting and magnetic properties, and the advances in synthetic methodology and in the theoretical understanding of these systems will allow for the design of new materials with predictable physical properties. The educational plan focuses on curriculum development, student mentoring, and research.