Molecular Clustering in a Two-Dimensional Metal-Ammonia Solution

Abstract

We have measured the in-plane x-ray diffraction pattern of the two-component ${\mathrm{K}}^{+}$ -N${\mathrm{H}}_3$ liquid layers in the ternary graphite intercalation compound K${\left(\mathrm{N}{\mathrm{H}}_3\right)}_{4.33}$ ${\mathrm{C}}_{24}$. The measured pattern is in semiquantitative agreement with the scattering calculated for a random distribution of coplanar hard ${\mathrm{K}}^{+}$ and N${\mathrm{H}}_3$ disks, provided that the ${\mathrm{K}}^{+}$ ions are bound symmetrically to four N${\mathrm{H}}_3$ molecules. We show that the K-N${\mathrm{H}}_3$ layers constitute the two-dimensional structural analog of the well-known bulk three-dimensional K-N${\mathrm{H}}_3$ metal-ammonia solutions.