Is there an N³⁻ ion in the crystal structure of the ionic conductor lithium nitride (Li₃N)?

Abstract

The structure parameters of Li 3 N in the temperature range -120 to 20°C were refined both for neutral atoms (Li 0 and N 0 ) and for ions (Li + and N 3- ). For N 3- new scattering curves were used which were calculated by applying stabilizing Watson-sphere potentials for different radii. All structure parameters depend critically on the scattering curves used. However, only on the assumption of ions, and only for N 3- scattering curves corresponding to a small range of Watson radii, were physically meaningful structure parameters and R values down to 0.9% obtained. These structure refinements demonstrate that Li 3 N can be considered as an ionic crystal in which the N 3- ion, though unstable as a free ion, is stabilized by the surrounding Li + ions.