A New Polymorph of ZrW₂O₈ Prepared Using Nonhydrolytic Sol−Gel Chemistry

Abstract

A new polymorph of ZrW2O8, structurally related to trigonal ZrMo2O8, has been prepared at low temperatures using nonhydrolytic sol−gel chemistry. Its identity was established by powder X-ray diffraction, energy dispersive X-ray analysis, and extended X-ray absorption fine structure (EXAFS). This material is denser than the previously reported cubic and orthorhombic forms of ZrW2O8 and decomposes into the binary oxides on prolonged heating at 700 °C. An EXAFS investigation of the crystallization of “ZrW2O8” gels, prepared by nonhydrolytic methods, suggests that the coordination environments of the cations in the heat-treated gels evolve toward those found in the new form of ZrW2O8 prior to the crystallization of this product.

Preparation and properties of negative thermal expansion zirconium tungstate thin films deposited by radio frequency magnetron sputtering

“…Figure 1b shows the XRD spectrum of as-deposited thin film annealed at 740 °C; the product is a trigonal ZrW 2 O 8 thin film. The diffraction pattern is very similar to the one reported previously [9,14]. As shown in Fig.…”

“…Several preparation techniques have been described in attempts to synthesize ZrW 2 O 8 thin films [8,9]. Sutton and Talghader reported NTE thin films deposited by electronbeam evaporation and reactive co-sputtering.…”

Influence of sodium dodecyl benzene sulfonate (SDBS) on the morphology and negative thermal expansion property of ZrW2O8 powders synthesized by hydrothermal method

“…ZrW 2 O 8 will decompose into zirconium oxide (ZrO 2 ) and tungsten oxide (WO 3 ) as it cools down slowly from its stable state which is the difficult point for getting single phase product via solid state reaction and co-precipitation method, as well as the volatility of WO 3 . Sol-gel route [15] can reduce the heat-treatment temperature. However, the cycle is too long.…”

Single crystal growth of ZrW2O8 by hydrothermal route

“…Apparently, it is difficult to control this procedure and obtain high-quality ZrW 2 O 8 crystals because WO 3 is easily volatilized at high temperatures. Several routes have been proposed to prepare ZrW 2 O 8 , including solid combustion [15,16], co-precipitation [15,17], solgel method [15,18,19], microwave synthesis [20], and hydrothermal synthesis [15]. Recently, the single crystal growth of ZrW 2 O 8 was reported by Kowach [21] at a high temperature.…”