title: Synthesis, structural characterization, and thermal stability of a new layered germanate structure, Na4Ge16O28(OH)12.
abstract: The new layered germanate structure Na4Ge16O28(OH)12 has been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, FTIR, and SEM. The crystal lattice parameters are a = 7.3216(6) A, b = 14.3986(9) A, c = 7.7437(6) A, alpha = 90.0 degrees, beta = 100.179(7) degrees, gamma = 90.0 degrees, and V = 803.5(1) A3. The space group is C2/m with Z = 1. The germanium oxide sheets are connected non-covalently via electrostatic interactions with the sodium cations and H-bridging. At temperatures above 400 degrees C, the structure starts decomposing into sodium enneagermanate (Na4Ge9O20), germanium dioxide, and water as determined by powder X-ray diffraction, TGA, DTA, DSC, and GCMS.
authors.affiliation: Ceramic Membrane Centre The Pore, University of Technology Delft, Julianalaan 136, 2628 BL Delft, The Netherlands.
authors.forename: Annemieke W C
authors.initials: AW
authors.lastname: van den Berg
authors.forename: Govert
authors.initials: G
authors.lastname: Baak
authors.forename: Hendrikus
authors.initials: H
authors.lastname: van Koningsveld
authors.forename: Jacobus C
authors.initials: JC
authors.lastname: Jansen
authors.forename: Thomas
authors.initials: T
authors.lastname: Maschmeyer