Direct synthesis of alkali-metal and ammonium pentafluoroperoxytitanates(IV), A₃[Ti(O₂)F₅], and first synthesis and structural assessment of alkali-metal and ammonium difluorodiperoxytitanates(IV), A₂[Ti(O₂)2F₂]

Abstract

Yellow alkali-metal and ammonium pentafluoroperoxytitanates(IV), A,[Ti(0₂)Fs] (A = Na, K, NH₄), have been synthesized directly from the reaction of Ti0₂ in 40% HF with 30% H₂0₂ at pH 6 maintained by the addition of the corresponding alkali metal or ammonium hydroxide. Novel alkali-metal and ammonium difluorodiperoxotitanates(IV), A₂[Ti(0₂)₂F₂]( A = K, NH₄), have been synthesized from the reaction of a solution of Ti0₂ in 40% HF with 30% H₂0₂ at pH 9 maintained by the addition of the corresponding AOH, followed by precipitation with ethanol. The compounds are all diamagnetic and permit molar conductance measurements. The IR and laser Raman spectra suggest that the peroxide groups are bonded to the Ti⁴⁺ center in a triangular bidentate (C_2vJ manner and that v_o-o decreases with the increase in the number of coordinated peroxide groups.