Comparison of Reactivity Based on Intercalation and Host Lattice Reconstruction. Two Routes for the Conversion of the Lamellar Solid Hydrogen Uranyl Phosphate to a Lamellar Hydrate of Uranyl Phosphate

Download or read book Comparison of Reactivity Based on Intercalation and Host Lattice Reconstruction. Two Routes for the Conversion of the Lamellar Solid Hydrogen Uranyl Phosphate to a Lamellar Hydrate of Uranyl Phosphate written by Guy L. Rosenthal and published by . This book was released on 1987 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The lamellar solid hydrogen uranyl phosphate can be quantitatively converted to a lamellar hydrate of uranyl phosphage by two routes: an intercalative ion-exchange reaction with aqueous uranium oxide ions and thermal decomposition in an aqueous slurry. An X ray powder pattern of the product can be indexed in tetragonal symmetry with an interlammelar spacing of 11.1 angstrom, expanded from a valve of 8.69 angestrom in hydrogen uranyl phosphate (HUP). Conversion of HUP to UP is accompanied by a drastic diminution in photoluminescence lifetime and intensity. Arrhenius parameters derived from the rates of the intercalation and thermal decomposition reactions indicate that they proceed by quite different mechanisms: the intercalation reaction proceeds with an apparent activation energy, of 12 plus or minus 2 kilo calories/mole and is characterized by a value of 30 plus or minus 2 kilo calories/mole. Samples of UP, obtained by either method, can be converted back to HUP by the action of dilute phosphoric acid in an aqueous slurry at room temperature. Possible mechanisms for these reactions are discussed.