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.