Investigation of the structure, phase transitions, molecular dynamics, and ferroelasticity of organic–inorganic hybrid NH(CH(3))(3)CdCl(3) crystals

Understanding the physical and chemical properties of the organic–inorganic hybrid NH(CH(3))(3)CdCl(3) is essential for its application. Considering its importance, a single crystal of NH(CH(3))(3)CdCl(3) was grown with an orthorhombic structure at 300 K. The phase transition temperatures were determined to be 345 (T(C3)), 376 (T(C2)), and 452 K (T(C1)) (phases IV, III, II, and I, respectively, starting from a low temperature). The partial decomposition temperature was 522 K (T(d)). Furthermore, the NMR chemical shifts of the (1)H, (13)C, and (113)Cd atoms of the cation and anion varied with increasing temperature. Consequently, a significant change in the coordination geometry of Cl around Cd in CdCl(6) and a change in the coordination geometry of H in NH was associated with changes in the N–H⋯Cl hydrogen bond near the phase transition temperature. The (13)C activation energy E(a) obtained from the spin-lattice relaxation time was smaller than that of (1)H E(a), suggesting that energy transfer around (13)C is easier. Additionally, a comparison of the twin domain walls measured via optical polarizing microscopy and Sapriel's theory indicated that the crystal structure in phase III was more likely to be orthorhombic than hexagonal.