text: The infrared spectrum of the compound in frozen argon indicates that the isolated  molecule is planar with D symmetry.
  A Scientific study of the stability of this and other metal trihalides at 50 °C was published by Nelsoon and Sharpe in 1956.
  Aerodynamic properties for the gas phase have been determined by the Glushko Thermocenter of the Russian  Academy  of  Sciences.