In situ powder X-ray diffraction, synthesis, and magnetic properties of the defect zircon structure ScVO(4-x)

Shahid P Shafi; Matthew W Kotyk; Lachlan M D Cranswick; Vladimir K Michaelis; Scott Kroeker; Mario Bieringer

doi:10.1021/ic900927j

In situ powder X-ray diffraction, synthesis, and magnetic properties of the defect zircon structure ScVO(4-x)

Inorg Chem. 2009 Nov 16;48(22):10553-9. doi: 10.1021/ic900927j.

Authors

Shahid P Shafi¹, Matthew W Kotyk, Lachlan M D Cranswick, Vladimir K Michaelis, Scott Kroeker, Mario Bieringer

Affiliation

¹ Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2.

PMID: 19894769
DOI: 10.1021/ic900927j

Abstract

We report the formation pathway of ScVO(4) zircon from ScVO(3) bixbyite with emphasis on the synthesis and stability of the novel intermediate defect zircon phase ScVO(4-x) (0.0 < x <or= 0.1). The formation pathway has been investigated by means of thermogravimetric/differential thermal analysis and in situ powder X-ray diffraction. The oxidation of ScVO(3) to ScVO(4) involves two intermediates of composition ScVO(3.5+y) (0.00 <or= y <or= 0.22) and the novel phase ScVO(4-x). ScVO(4-x) crystallizes in the defect zircon structure in space group I4(1)/amd (141) with a = 6.77761(5) A and c = 6.14045(8) A. Oxygen defect concentrations in bulk ScVO(4-x) samples range from 0.0 < x <or= 0.1. ScVO(4-x) is compared with the fully oxidized zircon structure ScVO(4) using powder X-ray diffraction, neutron diffraction, and bulk magnetic susceptibility data as well as (45)Sc and (51)V solid state NMR spectroscopy. ScVO(4-x) can only be obtained by oxidation of ScVO(3) or ScVO(3.5+y) while the reduction of ScVO(4) does not yield the novel defect structure. Mechanistic insights into the oxidative formation of ScVO(4) via the defect structure are presented.