ON THE AVERAGED CRYSTAL-STRUCTURE OF THE TLZN1.5-XF10-2X (X-APPROXIMATE-TO-0.15) NONSTOICHIOMETRIC PHASE(XZR1.5)

A new phase with the TlZn1.5+xZr1.5-xF10-2x (x = 0.15) formula has bee n characterized during the investigation of the TlF - ZnF2 - ZrF4 syst em. This phase crystallizes in the orthorhombic system with unit cell dimensions: a = 3.994(1)Angstrom, b = 6.531(1)Angstrom, c = 7.698(1)An gstrom and space group Pmmm (n(o)47), Z = 1. The structure was solved by conventional Patterson and Fourier methods and refined by full matr ix least-squares techniques to a conventional R of 0.041 (R-W = 0.044) for 404 independent reflections recorded on an automatic four-circle diffractometer. This structure closely related to that of RbIn3F10 is characterized by a random distribution of both Zn2+ and Zr4+ and a del ocalization of the Tl+ ions in the pseudo hexagonal channels parallel to the [100] direction.