Crystal structure at (T = 295 and 173 K) of[(NH4)0.63Li0.37]2TeBr6

The crystal structure of lithium–ammonium hexabromotellurate[(NH4)0.63Li0.37]2TeBr6, has been determined by X-ray single crystal analysis at room temperature. The space group is Fm 3¯ m, with a = 10.7200(12) Å. Differential scanning calorimetry reveals three anomalies at 195, 395 and 498 K. Below 195 K the phase transition leads to a tetragonally distorted structure. This low temperature phase shows an anti-ferrorotative displacement of TeBr62- octahedra with a tilt angle 6 °. The title compound has an anti-fluorite-type arrangement of NH4+/Li+ and octahedral TeBr62- anions.