Zirconium tungstate hydroxide hydrate revisited: Crystallization dependence on halide and hydronium ions

Journal Article · Sat Dec 15 04:00:00 EST 2007 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2007.10.012· OSTI ID:21043780

Camper, DeMarco V; Gates, Stacy D ^[1]; Lind, Cora ^[1]

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1. 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, Journal Name: Journal of Solid State Chemistry Journal Issue: 12 Vol. 180; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
BROMIDES
CHLORIDES
CRYSTALLIZATION
HYDRATES
HYDROCHLORIC ACID
HYDROXIDES
KINETICS
OXONIUM IONS
THERMAL EXPANSION
ZIRCONIUM TUNGSTATES