Structural transformations and H-bonds in Li1-xHxIO3 mixed crystals

Raman study of crystals

“…Le Roy et al [7] showed that the Li 1−x H x IO 3 crystals with x in the interval 0.22 < x < 0.36 present a hexagonal symmetry, belonging to the same C 6 6 (P 6 3 ) space group as the α-LiIO 3 crystal. In the case of the pure compound LiIO 3 , the IO − 3 pyramidal anions occupy C 3 sites (Wyckoff position b), and a correlation analysis shows that the internal modes ν 1 and ν 2 of the iodate anion belong to the A and B irreducible representations and the internal modes ν 1 and ν 2 belong to the E 1 and E 2 representations of the C 6 point group [13].…”

“…Avdienko et al [5], ascertained, with the support of their Raman results, that the structure and symmetry of Li 1−x H x IO 3 crystals would be different from those of α-LiIO 3 and α-HIO 3 . Barabash et al [6] performed a Raman study of polycrystalline samples of Li 1−x H x IO 3 over a wide range of concentration x, and observed that the Raman spectra in the range 0.22-0.36 were composed of anomalous broad bands, characteristic of disordered crystals. It was shown in this study that the Raman spectra of solid solutions for x > 0.36 corresponded to the superposition of this broad-band spectrum with that of α-HIO 3 crystal.…”

“…This result led them to conclude that the solid solutions could not be isomorphous with α-LiIO 3 . However, in 1990, Le Roy et al [7] determined the room temperature structure of Li 1−x H x IO 3 (x = 0.33) by x-ray singlecrystal and neutron powder diffraction, and concluded that it presents a hexagonal average symmetry, belonging to the same C 6 6 (P 6 3 ) space group as α-LiIO 3 . Figure 1 shows the crystal structure of the hydrated solid solution as determined in reference [7].…”

“…In order to elucidate why the previous Raman studies [5,6] and the neutron and x-ray results [7] are at variance, a complete polarized Raman study of Li 1−x H x IO 3 single crystals for several values of x (x 0.36) was performed, using different scattering geometries. The results and their analysis are presented in the following.…”

Correlation between Structural, Infrared and Nuclear Quadrupole Resonance Data of Iodates

“…A slight deviation of q from zero for a-LiI0 3 [10] may be explained by the formation of Li^^H^ I0 3 solid solutions during a-LiI0 3 growth from acid solutions [11].…”