A nuclear magnetic resonance study of the structural properties and molecular motions of Li2KH(SO4)2 and LiKSO4 single crystals

The structural properties and relaxation mechanisms of Li2KH(SO4)2 crystals were determined using the temperature dependences of NMR spectra and the spin-lattice relaxation times (T1) of their 1H, 7Li, and 39K nuclei. The results obtained were compared with the previously reported physical properties of LiKSO4 crystals. The substitution of the potassium ions with protons in the LiKSO4 crystals were variations in the phase transition temperatures, and the non-appearance of ferroelastic properties. The 7Li T1 for the Li2KH(SO4)2 crystals was much shorter than the 7Li T1 for the LiKSO4 crystals, and these findings indicate that the presence of the protons in Li2KH(SO4)2 causes the Li ions to move with greater freedom.