Crystal Structure of NH4NaTiF6and Internal Mobility of the Complex Anions

Single crystals of NH₄NaTiF₆are studied by X-ray diffraction analysis (automated diffractometer, MoK radiation, graphite monochromator, sin/ 1.0 Å^–1, 1566 reflections with I> 3(I), anisotropic least squares method to R= 0.045 and R _w= 0.040). The compound belongs to the NaRbSnF₆structural type. The types of internal motions of the complex ions NH₄ ⁺and TiF₆ ^2–are determined in the temperature range 200–500 K and compared with the motion of ionic groups in (NH₄)₂TiF₆and Na₂TiF₆crystals.