Please use this identifier to cite or link to this item:
Title: The first hafnium germanate with garnet-type of structure: mild hydrothermal synthesis, crystal structure and new mechanism of hydroxyl inclusion
Author: Ferdov, Stanislav
Lin, Zhi
Keywords: Hafnium garnet
Hydrothermal synthesis
Hydroxyl inclusion
Crystal structure
Issue Date: May-2019
Publisher: Elsevier
Abstract: Sodium hafnium germanate, Na3Hf1.7Ge3O10(OH)1.8, with garnet-type of structure was synthesized as a single phase, nanoparticles (100–600 nm) at mild hydrothermal conditions (230 °C) and autogenous pressure. The structure was solved ab initio from powder X-ray diffraction data and subsequently refined [Rexp: 6.10, Rwp: 7.26, Rp: 5.39, GOF: 1.19, RB: 1.50] by the method of Rietveld. The solid crystallizes in cubic space group Ia-3d (230), with a = 12.6819(2) Å, V = 2039.65(1) Å3 and Z = 8. The structure is built up of rare combination of two tetravalent (Ge4+ and Hf4+) and one monovalent (Na+) cation alternating in form corner-sharing GeO4 tetrahedra and HfO6 octahedra whose negative charge is compensated by Na+ residing in dodecahedral coordination. Unlike the typical tetrahedral site disorder in hydrogarnets (hydrogrossular, hibschite, and katoite) we found that the octahedral position of the heavy Hf4+ cation is partly vacant which reveals alternative mechanism of charge unbalance leading to incorporation of hydroxyl group. Furthermore, the synthesized material is the first hafnium germanate with garnet-type of structure and the second known sodium hafnium germanate.
Peer review: yes
DOI: 10.1016/j.jssc.2019.02.031
ISSN: 0022-4596
Appears in Collections:CICECO - Artigos
DQ - Artigos

Files in This Item:
File Description SizeFormat 
The first hafnium germanate with garnet-type of structure.pdf4.81 MBAdobe PDFView/Open

Formato BibTex MendeleyEndnote Degois 

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.