The coordination of Cu(II) in a concentrated copper nitrate solution

Abstract
The first-order difference method of neutron diffraction has been applied to a 1.00 molal (mol kg-1) Cu(NO3)2 heavy water solution. The results show a nearest-neighbour distance given by rCuO=1.96+or-0.03 AA, a hydration number n0Cu=4.0+or-0.2 and are consistent with a Jahn-Teller distortion of the Cu2+(aq) complex to give a (4+2) coordination group.