Poly[perfluorotitanate(IV)] Salts of [H3O]+, Cs+, [Me4N]+, and [Ph4P]+ and about the Existence of an Isolated [Ti2F9]- Anion in the Solid State

The increase in the size of monocations (A(+)) does not favor the formation of [Ti2F9](-) against [Ti4F18](2-) salts (with isolated [Ti2F9](-) or [Ti4F18](2-) anions, respectively) as previously proposed (Passmore, J.; et al. Angew, Chem., Int. Ed. 2005,44, 7958-7961). The crystal structure determination of [Me4N](+) and [Ph4P](+) salts showed that both compounds are [Ti4F18](2-) salts; i.e., [Me4N](2)[Ti4F18] and [Ph4P](2)[Ti4F18] were obtained instead of [Me4N][Ti2F9] and [Ph4P][Ti2F9]. The product of the reaction of CsF with 2TiF(4) Could be formulated as CsTi2F9; however, instead of isolated [Ti2F9](-) anions, infinite ([Ti2F9](-))(n) double chains are present. In the case of H3OTi2F9, a similar result was obtained. On the basis of the similarities of vibrational spectra of CsTi2F9 and NF4Ti2F9, it is also unlikely that the latter consists of isolated [Ti2F9](-) ions.