Nuclear magnetic resonance of14N in ammonium aluminum alum

Behavior of H2O surrounding NH4+ and Al3+ in NH4Al(SO4)2·12H2O by 1H MAS NMR, 14N NMR, and 27Al NMR

In order to understand the thermodynamic properties and structural geometry of NH₄Al(SO₄)₂·12H₂O, we studied the magic angle spinning nuclear magnetic resonance (MAS NMR) and static NMR as a function of temperature.

Local structure and tunneling kinetics of ammonium aluminum alum by infrared hole-burning

The title compound, crystallized with a few percent of deuterium, contains some NH(3)D(+) and HOD. At low temperatures, five N-D stretch bands are observed. These belong to two ammonium sites with apparent C(s) symmetry in the low-temperature phase. The N-D bands can be hole-burned with an infrared laser. Burning bands belonging to the A-sites transforms some of them to the higher-energy B-sites. The A- and B-sites probably differ from each other by the arrangement of water and sulfate about the ammonium.