Abstract
New developments in perovskite-type N(CH(3))(4)MnCl(3) single crystals were examined, with a focus on their high-temperature phases. The phase transition temperature (T(C)) was established as being 390 K via differential scanning calorimetry and powder X-ray diffraction analyses. At 300 K, the single-crystal structure has hexagonal symmetry and exhibits thermal stability up to a high temperature of approximately 680 K. Additionally, (1)H and (13)C nuclear magnetic resonance (NMR) chemical shifts displayed continuous changes with temperature, without any anomalous behavior observed near T(C). The (1)H spin-lattice relaxation time, which represents the molecular motion of (1)H, shows slight changes near T(C). The phase transition from phase I to I ('), associated with changes in the rotational degrees of freedom of N(CH(3))(4)(+) molecules, is considered second-order. The small change between phases I and I (') is consistent with a change in the space group in the same hexagonal structure previously reported. These physical properties indicate the potential applications of N(CH(3))(4)MnCl(3) as an organic-inorganic hybrid perovskite material.