Ilmenite-type Na2(Fe2/3Te4/3)O6

Abstract

Na2(Fe2/3Te4/3)O6 (Z = 3) or Na3(FeTe2)O9 (Z = 2), trisodium iron(III) ditellurium(VI) nonaoxide, adopts the ilmenite (FeTiO3, Z = 6) structure type with the Ti site (site symmetry 3.) replaced by Na and the Fe site (site symmetry 3.) replaced by a mixed-occupied (FeIII,TeVI) site in a Fe:Te ratio of 1:2. Whereas the [(Fe,Te)O6] octahedron is only slightly distorted, the [NaO6] octahedron shows much stronger distortions, as revealed by a larger spread of the bond lengths and some distortion parameters.

Keywords

• crystal structure
• mixed occupancy
• isotypism
• close-packed structure