A New Polymorph of VO2Prepared by Soft Chemical Methods

✍ Scribed by Douglas Hagrman; Jon Zubieta; Christopher J. Warren; Linda M. Meyer; Michael M.J. Treacy; Robert C. Haushalter

• Book ID: 102604177
• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 429 KB
• Volume: 138
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1997.7575

✦ Synopsis

A novel polymorph of VO 2 , designated VO 2 (C), has been prepared by dehydration of the new layered vanadium oxide hydrate, VO 2 • 1/2 H 2 O. The hydrate is prepared in high yield as a single phase from the hydrothermal reaction of the hydrolyzate of VCl 4 and NaOH in a molar ratio of 1 : 4.5 for 96 hours at 200°°C. The hydrate crystallizes in the tetragonal space group I4/mmm, with a ‫؍‬ 3.7211(6) A s , c ‫؍‬ 15.421(1) A s , Z ‫؍‬ 4, and R ‫؍‬ 0.045 as determined by X-ray single crystal diffraction. The structure consists of layers of VO 5 square pyramids, each of which shares its four basal edges with four neighboring VO 5 square pyramids. Water molecules that reside between the layers can be removed reversibly to give the new layered oxide VO 2 (C).