CHEMISTRY IN POLAR INTERMETALLIC COMPOUNDS - THE INTERSTITIAL CHEMISTRY OF ZR5SN3

The formation of stoichiometric Zr5Sn3Z derivatives through incorporation of Z within chains of confacial zirconium octahedra in the Zr5Sn3 (Mn5Si3-type) parent has been studied principally through reactive powder sintering in the range 1000-1350-degrees-C and by X-ray diffraction means. Examples with Z = B, C, N, 0, Al, Si, P, S, Cu, Zn, Ga, Ge, Sn, As, and Se have been quantitatively synthesized and characterized as powders. Complications are noted with arc-melting methods and for Z = Fe, Co, Ni where mixed Z-Sn interstitials occur. Single crystal diffraction for Z = C, 0, and Ge and Rietveld powder refinement for Ga demonstrate how the host Zr6 cavities contract or expand to accommodate Z. The Zr5Sn3S. System at 1050-degrees-C is nonstoichiometric over the range 1 > x > approximately 0.5. Volume trends as a function of Z follow the metallic/covalent radii of Z well.