Crystal structure of hexa-amminecobalt(III) pentachlorocadmate(II)

Abstract

The crystal structure of the title compound was determined from diffractometer measurements and refined to R 0·020 for 835 reflections. Unit cell dimension a= 22·379(2)Å, space group Fd3c, with Z= 32. The positions of the Co and Cd atoms are fixed by symmetry to sites of and 32 symmetry, respectively. The unique Co–N bond length is 1·960(6)Å while the N–Co–N angle is 89·51(12)°. The two independent Cd–Cl distances in the trigonal bipyramidal CdCl₅^3– anion are Cd–Cl(ax) 2·526(1) and Cd–Cl(eq) 2·561(2)Å. Thus, for Cd^II(d¹⁰), the difference [0·036(1)Å] between axial and equatorial M–Cl bonds is considerably less than that found in Cu^II(d⁹). This result is in accord with spectral studies of Cu^II species which have been interpreted to mean that, in the trigonal bipyramidal case, the d orbital of highest energy is d_z².