The structure of [(NH4)0.69K0.31]2CuCl4.2H2O single crystal at room temperature has been determined from X-ray diffraction of the MoKα. line (λ = 0.7122 Å). The title compound crystallises in the space group P42/mnm and has a unit cell dimensions: a = b = 7.5497(2) Å, c = 7.9491(2) Å, Z = 2. The refinement converged to R = 0.024 and wR2 = 0.064 for 669 observed reflections (with |Fo| = 4σ(|Fo|). The Cu2+ has a distorted octahedral coordination consisting of two Cl(1) ions at 2,945(2) Å, two Cl(2) ions at 2.2708(4) Å and two H2O molecules at 1.9587(2) Å. Each of the water molecules is trigonally coordinated and forms two equivalent O-H..Cl(1) hydrogen bonds with an O..Cl(1) length of 3.130(2) Å. Four Cl(1) and four Cl(2) ions form a distorted cube around the K+/NH4+ ions. Thermal studies indicate the presence of phase transition at T = -67°C. The Raman and IR have been undertaken at room temperature.
M. Khelifi, R. Zouari, J. Jaud, A. Ben Salah
Crystal structure, mixed compound, Copper salts