Neue Untersuchungen an quaternären Fluoriden

New Investigations on Quaternary Fluorides For the first time the quaternary fluorides M¹₂M^IILnF₇ (M¹ = Na, Ag; M^II = Ca, Cd; Ln = Er? Lu) had been prepared and examined with with X-ray diffraction. All these compounds crystallize in a cubic face-centered lattice. Colourless single crystals of Na₂CdYbF₇ were obtained and the structure was determined. Na₂CdYbF₇ crystallizes in the space group Fm3M-O⁵_h, No. 225. The single-crystal diffraction data refer to a Defect-Fluorite-Structure. The R-value for 332 observed (29 independend) reflections is 2.2%.