A least-squares method for the identification of resonant groups from NMR powder spectra. Identification of oxonium and hydroxyl ions in hydrated uranates

摘要: Abstract A general method to calculate NMR powder spectra with a predetermined precision is described. The calculated spectrum for one resonant group depends on short and long range dipolar interactions, α β the proportion of in chemical formula. We propose least-squares determine best values parameters. To choose initial values, we use some easily measurable characteristic experimental relations between them various Thus, mathematical suggested can be used identify groups state precisely formula polycrystalline solid. theoretical calculation applied hydrated uranates. hydration water shown exist form oxonium hydroxyl ions according Brasseur's hypothesis. proposed refute formulas as well specify proton-proton distance equilateral triangle found 1.72 A. limits are discussed. Dehydration experiments show that first dehydration step corresponds departure ions.