The structure of H2TiO3—a short discussion on “Lithium recovery from salt lake brine by H2TiO3”

Abstract

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 (33) and the peak (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].