Infrared and Raman spectroscopic investigations of methylammonium haloantimonates(III), [N(CH3)4−nHn]3 Sb2X9 (n = 0–3, X = Cl or Br), through their phase transitions☆

摘要: Abstract Infrared and Raman spectra of methylammonium chloroantimonates(III) the general formula [N(CH 3 ) 4− n H ] Sb 2 Cl 9 with = 0, 1, bromoantimonate(III), (CH NH Br , have been investigated in detail across their phase transitions. Vibration modes due to CH deformation those involving ( 3) groups show significant changes transitions chloroantimonates, besides anion. The anion differ number since nature itself changes, free being present only quarternary compound. high-temperature phases chloroantimonates seem involve random orientations methylamino groups; a plastic-type state clearly manifests trimethyl tetramethylamino derivatives. A transition is predicted all below 150 K, based on bands at low temperatures. Changes IR accompanying Bi are similar these compounds + cations ard oriented randomly.