The Crystal Structure of Sb0.92V0.92O4, Determined by Neutron and Dual Wavelength X-Ray Powder Diffraction

✍ Scribed by Staffan Hansen; Kenny Ståhl; Roland Nilsson; Arne Andersson

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 313 KB
• Volume: 102
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1993.1043

✦ Synopsis

A phase of approximate composition (\mathrm{SbVO}{4}) has been reported in the literature as a key component in new catalysts for the ammoxidation of propane to acrylonitrile. (\mathrm{Sb}{0.92} \mathrm{~V}{0.92} \mathrm{O}{4}) was prepared by heating equimolar amounts of (\mathrm{Sb}{2} \mathrm{O}{3}) and (\mathrm{V}{2} \mathrm{O}{5}) in air at (1073 \mathrm{~K}) for (2 \mathrm{hr}). The chemical composition was determined by thermogravimetry and energy dispersive X-ray microanalysis. The crystal structure at (293 \mathrm{~K}) was determined, from three powder diffraction data sets recorded with (\mathrm{Cu} K \alpha_{1}, \mathrm{Mo} K \alpha), and (1.040(1)-\AA) neutron radiation, using the Rietveld method. Crystal data: (\mathrm{Sb}{0.92} \mathrm{~V}{0.92} \mathrm{O}{4}, Z=1, a=) (4.625(4), c=3.040(2) \AA), tetragonal space group (P 4{2} / \mathrm{mmm}, M_{\mathrm{r}}=222.87, D_{\text {calc }}=5.69 \mathrm{~g} / \mathrm{cm}^{3}). All three data sets yield a cation deficient rutile structure and final profile (R)-values of (3.5,6.3), and (3.5 %). Bond valence sums. calculated from the experimentally determined bond lengths, indicate the oxidation states to be (\mathrm{Sb}^{5+}) and (\mathrm{V}^{3+} / \mathrm{V}^{4+}), leading to the formula (\mathrm{Sb}{0.92}^{5+} \mathrm{V}{0.28}^{3+} \mathrm{V}{0.64}^{4+} \square{0.16} \mathrm{O}{4}) (the square denotes metal ion vacancies). Bond valence calculations also suggest that (\mathrm{OSb}{2} \square) is the most favorable configuration for an oxygen associated with a metal vacancy. O 1993 Academic Press. Inc.