Molecular motions and phase changes in the perovskite-type compound (C10h21nh3)2zncl4
Fenrych J.2, Reynhardt E. C.1, Jurga S.2, Jurga K.2
- 1Department of Physics, University of South Africa, P.O. Box 392, Pretoria, 0001, South Africa
- 2Institute of Physics, A. Mickiewicz University, Grunwaldzka 6, Poznan, 60-780, Poland
Molecular Physics, 78 (5), pp.1117-1128, 1993
DOI:: 10.1080/00268979300100721
Abstract:
A virgin sample of polycrystalline (C10H21NH3)2ZNCl4 shows two phase transitions, at 284 K and 363 K. In the low-temperature phase threefold reorientations of methyl and NH3 groups dominate the nuclear magnetic resonance relaxation results. The motion of the NH3 groups can be described as a threefold jump among three potential minima of which one is shallower than the other two. In the intermediate temperature phase a defect motion of chain ends has been identified. In the high-temperature phase the spacing between adjacent layers of ZnCl4 tetrahedra is increased by ~ 16% due to the non-intercalation of the chains. In this phase the chains experience a high degree of mobility, which is partly due to the diffusion of chain defects along the chain. On cooling the sample from the high-temperature phase, it transforms to the intermediate phase, but the transition to the low-temperature phase is absent. © 1993 Taylor & Francis Group, LLC.
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