On the existence of pyrophosphates of tetravalent metals having a layered structure

摘要: Abstract After an accurate investigation of the thermal behaviour (TG and DTA curves) several samples α-Zr(HPO 4 ) 2 ·H O α-Ti(HPO O, prepared both by refluxing HF procedures, γ-Zr(HPO ·2 H γ-Ti(HPO new pyrophosphate phases tetravalent metals have been isolated. The structure these compounds, deduced from X-ray diffraction data, density measurements considerations bond length angles, arises packing layers α γ type, identical to those present in starting materials held together POP bridges. These layered M(IV)P 7 are obtained after condensation process HPO groups γ-M(IV)(HPO stable until transition respective cubic pyrophosphates takes place. range stability changes on going phase part depends degree crystallinity and/or crystal size exchanger. chemical implications α- γ-L-M(IV)P examined discussed.