1H and 133Cs nuclear magnetic resonance study of the NH4 and Cs occupation rates of mixed (NH4)2−xCsxZnCl4 (x = 0, 1, and 2) crystals

Abstract

The NMR spectra and the spin–lattice relaxation times, T1, of the 1H and 133Cs nuclei in (NH4)2−xCsxZnCl4 (x=0, 1, and 2) single crystals were determined by using NMR spectroscopy. We investigated the crystallographic structures of these crystals by determining the NH4 and Cs occupation probabilities of the two cationic sites. Our NMR experimental results confirm that in (NH4)2ZnCl4 there are two crystallographically inequivalent NH4 groups, NH4(1) and NH4(2), occupying the A1 and A2 sites, and that in Cs2ZnCl4 there are two crystallographically inequivalent Cs ions, Cs(1) and Cs(2), occupying the A1 and A2 sites. Both types of NH4 ions and both types of Cs ions are found in mixed NH4CsZnCl4 crystals; the occupation rates of the two different sites are 1 and 1 for Cs(1) and Cs(2), respectively, and 1 and 1 for NH4(1) and NH4(2), respectively.