# NMR study of fast protonic conduction in layered $HLa_2NbTi_20_{10}{\cdot}1. 5H_2O$

Mangamma, G and Bhat, V and Gopalakrishnan, J and Bhat, SV (1992) NMR study of fast protonic conduction in layered $HLa_2NbTi_20_{10}{\cdot}1. 5H_2O$. In: Solid State Ionics, 58 (3-4). pp. 303-309.

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## Abstract

Protonic motion in the layered compound $HLa_2NbTi_2O_{lO}{\cdot}1.5H_2O$ has been studied by various NMR experiments. The $^1H$ NMR relaxation times $T_1,T_{1p}$ and $T_2$ have been measured as functions of temperature. At 110 K, the rigid-lattice spectrum is observed which consists of a strong central signal flanked on either side by broader wings. From the line shape analysis of the spectrum it is concluded that the protons of the water molecules and the cage protons exist distinctly and do not form $H_3O^+$ ions. The signals show motional narrowing beginning at $\sim 190 K$ indicating the onset of protonic diffusion. The relaxation data have been analysed taking into account the layered structure of the material. Magic angle spinning shows a single signal at 4.47 ppm with respect to TMS. The mechanism of protonic motion in $HLa_2NbTi_20_{10}{\cdot}1.5H_2O$ is discussed in the light of these NMR results.

Item Type: Journal Article Copyright of this article belongs to Elsevier. Division of Chemical Sciences > Solid State & Structural Chemistry UnitDivision of Physical & Mathematical Sciences > Physics 11 Aug 2006 19 Sep 2010 04:30 http://eprints.iisc.ernet.in/id/eprint/8028