Phase Transitions in CsSnCl3 and CsPbBr3 An NMR and NQR Study

The phase transitions in CsSnCl and CsPbBr have been studied by X-ray powder diffraction, by Br-NQR and by 'H-, Sn-, and Cs-NMR. At room temperature in air CsSnCl forms a hydrate which can be dehydrated to the monoclinic phase II of CsSnCl . The high temperature phase I has the Perovskite structure, as the X-ray and NMR experiments show. The three phases of CsPbBr , known from literature, have been corroborated. The results are discussed in the framework of the group ABX , A = alkalimetal ion, B = IV main group ion, and X = Halogen ion