Synthesis and Crystal Structure of InFeO3(ZnO)4

Abstract

AbstractInFeO3(ZnO)4 was prepared from binary oxides as starting materials at 1350 °C in sealed platinum tubes as an earth brown powder. Single crystals were grown from a K2MoO4 flux in sealed Pt‐tubes using cooling rates of –0.1 K min–1. The structure of InFeO3(ZnO)4 was refined in space group P63/mmc; No. 194 (a = 3.211(6) Å; c = 33.032(6) Å; Z = 2; R1 = 3.68 %) from XRD data and revealed a build‐up from alternate stacking of layers of edge‐sharing InO6 octahedra and 5 layers of corner‐sharing (Zn/Fe)O4 tetrahedra. Inversions of the (Zn/Fe)O4 tetrahedra occurs (i) at the InO6 octahedral layer and (ii) halfway in the wurtzite type region where the inversion boundary is built by cations in 4+1 trigonal bipyramidal coordination. The position of the cations in their oxygen surrounding is described by a factor t which quantifies the displacement of the cation from the center of a trigonal bipyramid towards one of the constituting tetrahedra. Refining the site occupation factors of the cations in the (Zn/Fe)O4 tetrahedra results in a clear and reasonable gradient for the distribution of iron. Refinement of the oxygen position reveals split positions for the oxygen atoms at the second inversion boundary in the center of the wurtzite type region which shows similarities to inversion domain boundaries at fivefold coordinated cations in the wurtzite type region of compounds of type ARO3(ZnO)m with m > 15. Thus, it is more likely to describe InFeO3(ZnO)4 as a closest‐packed structure of cations with oxygen filling the interstices.