Synthesis, characterization, and X-ray powder structure of K2ZrGe2O7

A potassium zirconinm pyrogermanate, K2ZrGe2O7, was synthesized hydrotherma lly at 180 degrees C from a mixture of zirconium propionate, GeO2, and KOH, The crystal structure was solved from in-house;X-ray powder data by direct methods and Fourier analysis. Refinement of the structure was effected by the Rietveld full-pattern technique. The compound is monoclinic, space grou p C-2/c, a = 9.9619(2) Angstrom, b = 5.5578(1) Angstrom, 12.9555(3) Angstro m, beta = 105.169(1)degrees, Z = 4, The structure is remarkably like that o f alpha-zirconium phosphate, Zr(HPO4)(2). H2O, except that the layers are c rosslinked by the pyrogermanate group to form a three-dimensional lattice, Exchange of the K+ ions is minimal as they are strongly held within the con fines of narrow tunnels, The relationship of this newly synthesized pyroger manate to a sodium zirconium pyrogermanate prepared hydrothermally at 500 d egrees C and Na3H(GeO4)(2) is discussed. (C) 1999 Academic Press.