ChemInform Abstract: Structure of the Cation N2H+ 7 with a Hydrogen Bond of Type N‐H...N in the Monoammonia‐Adduct of Ammonium Iodide.

Abstract

ChemInform Abstract NH4I•NH3 (I), prepared by exposure of NH4I to gaseous NH3 of 350-450 torr, crystallizes at 298 K in the cubic space group Pm3m with Z=1. The powder and single crystal XRD data confirm the presence of the title cation in (I). The N-N distance is determined to be 269 pm indicating a strong interaction between NH4+ and NH3. During cooling of (I), transitions to three other modifications with increasing degree of structural order are observed. (I) is tetragonal in the range 230-203 K (P4/mmm, Z=1) and transforms into an orthorhombic form (Z=2) at 203 K. The modification existing below 143 K is not identified. Cubic ND4I•ND3 directly transforms into the orthorhombic phase at 237 K.