The structure of H2TiO3-a short discussion on "Lithium recovery from salt lake brine by H2TiO3".

A short discussion on the structure of H2TiO3 presented in the article entitled Lithium recovery from salt lake brine by H2TiO3 (R. Chitrakar, Y. Makita, K. Ooi and A. Sonoda, Dalton Trans., 2014, 43, 8933) is presented. In our opinion, it is not correct to identify the phase of H2TiO3 as monoclinic. The XRD pattern of H2TiO3 differs substantially from that of Li2TiO3. XRD pattern simulation shows that the peak (1[combining macron]33) and the peak (2[combining macron]06) cannot be fully collapsed or substantially decrease in intensity by substitution of Li(+) with H(+) if H2TiO3 shares a similar space group and lattice parameters with Li2TiO3. A direct verification of a similar structure by N. V. Tarakina and co-workers may aid the confirmation of the structure. The layered double hydroxide type with the 3R1 sequence of oxygen layers is more reasonable for H2TiO3 and can be described as a stacking of charge-neutral metal oxyhydroxide slabs [(OH)2OTi2O(OH)2].