Fluoride crystal structures. Part XII. Trimeric technetium oxide tetrafluoride

Abstract

Technetium oxide tetrafluoride is dimorphic, having monoclinic and hexagonal forms. Crystals of the hexagonal form have space group P6₃/m, a= 9·00, c= 7·92 Å. The structure was refined by three dimensional least-squares methods, to R 0·108 for 368 independent reflections. In the crystal, octahedrally co-ordinated units are linked into trimers by cis-bridging fluorine atoms. The distorted octahedral arrangement around technetium is almost identical to that around molybdenum in the endless chain structure of molybdenum oxide tetrafluoride.