Zirconium tungstate hydroxide hydrate revisited: Crystallization dependence on halide and hydronium ions
- Department of Chemistry, MS 602, University of Toledo, Toledo, OH 43606 (United States)
The formation of zirconium tungstate hydroxide hydrate, a precursor to the negative thermal expansion material cubic zirconium tungstate, shows a strong dependence on hydrothermal reaction conditions. It was found that not only the acid concentration, but also the acid counterion plays a significant role in the crystallization of ZrW{sub 2}O{sub 7}(OH){sub 2}.2H{sub 2}O. High temperatures, high acid concentrations, and the presence of chloride or bromide ions promote the formation of well-crystallized ZrW{sub 2}O{sub 7}(OH){sub 2}.2H{sub 2}O. For low acid concentrations, a new zirconium tungstate hydrate polymorph is observed, which transforms to tetragonal ZrW{sub 2}O{sub 7}(OH){sub 2}.2H{sub 2}O at longer reaction times. A study of crystallization kinetics in hydrochloric acid is presented. - Graphical abstract: The formation of ZrW{sub 2}O{sub 7}(OH){sub 2}.2H{sub 2}O shows a strong dependence on reaction conditions. Both acid concentration and acid counterion play a significant role in the crystallization. High temperatures, high acid concentrations, and the presence of chloride or bromide ions promote the formation of well-crystallized ZrW{sub 2}O{sub 7}(OH){sub 2}.2H{sub 2}O. For low acid concentrations, a new zirconium tungstate hydrate polymorph is observed.
- OSTI ID:
- 21043780
- Journal Information:
- Journal of Solid State Chemistry, Vol. 180, Issue 12; Other Information: DOI: 10.1016/j.jssc.2007.10.012; PII: S0022-4596(07)00425-2; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
Similar Records
Influence of SO{sub 2} deposition on cement mortar hydration
A laboratory study of the effect of acetic acid vapor on atmospheric copper corrosion