Synthesis, Structure, and Properties of Potassium fac-Trichlorotrinitroiridate(III)

Potassium salt of the iridium(III) chloronitro complex fac -K 3 [Ir(NO 2 ) 3 Cl 3 ] is obtained in the interaction of the iridium(III) trinitrotriaqua complex with potassium chloride in an aqueous solution. The salt structure is analyzed by single crystal X-ray diffraction. Crystallographic data: a = 7.3460(3) Å, b = 12.9904(5) Å, c = 13.1841(6) Å, β = 93.924(1)°, space group P 2 1 / с , Z = 4, ρ cal = 3.026 g/cm 3 . In the crystal structure, molecules of the [Ir(NO 2 ) 3 Cl 3 ] 3– complex anion having a distorted octahedral geometry (Ir–N = 2.02-2.04 Å, Ir–Cl = 2.37-2.38 Å) are arranged in layers perpendicular to the с axis. Spectral characteristics (IR, Raman, UV-vis) of the salt are determined together with its transformations during thermolysis in the inert atmosphere. Experiments are performed on sorption of the [Ir(NO 2 ) 3 Cl 3 ] 3– complex on nickel hydroxide, which model iridium loss during the precious metal refining process by the precipitation scheme.