Synthesis and Crystal Structure of Ammine Copper(I) Cyanamide, Cu 4 (NCN) 2 NH 3

Ammine copper(I) cyanamide, Cu 4 (NCN) 2 NH 3 , was obtained as a white powder from the reaction between CuCl and H 2 NCN in concentrated ammonia solution. X‐ray and neutron diffraction experiments yield the hexagonal system with space group P 63 mc (no. 186) and a = 5.7661(1) Å, c = 10.7817(3) Å, and Z = 2. The structure is characterized by layers of monovalent copper ions with an average Cu–Cu distance of 2.89Å, and the layers are connected through two crystallographically independent NCN 2− units. While one Cu I is linearly bonded to an NCN 2− unit and an additional NH 3 molecule, the other Cu I is also linearly coordinated but by two NCN 2− groups; the Cu–N bonds lie between 1.86–1.98Å. The C–N bond lengths and angles evidence both NCN 2− groups as essentially linear cyanamides.