Synthesis and Study of Potassium Peroxypentafluorotantalate Monohydrate

摘要

Potassium peroxypentafluorotantalate monohydrate K_2TaO_2F_5 centre dot H_2O was synthesized by the introduction of hydrogen peroxide and potassium chloride into highly pure tantalum-containing fluoride solutions at 70 deg C followed by cooling of the mixture to room temperature at a rate of 10-15 K/h. The X-ray diffraction analysis revealed that K_2TaO_2F_5 centre dot H_2O crystallized in the monoclinic crystal system with the following unit cell parameters: a=8.965(2) A, b=8.966(2) A, c =9.257(2) A, beta=99.78(3) deg, Z=4, V_(unit cell)=733.3(5) A~3, rho_(calcd)=3.681 g/cm~3, FW=404.13, space group c_2~3=C2(5). The thermolysis of K_2TaO_2F_5 centre dot H_2O was studied at 160-1000 deg C, and the phases formed under specified conditions were determined.