
%0 Journal Article
%A Boutchard, CL 
%A Hitchman, MA 
%A Skelton, BW 
%A White, AH 
%T Crystal Structure and Electronic Spectrum of the Distorted Tetrahedral CuCl<sub>4</sub><sup>2-</sup> Ion in Bis(2-aminopyridinium) Tetrachlorocuprate(II) and Comparison With the Tetragonally Elongated Octahedral Complex Bis(2-aminopyrimidinium)tetrachlorocopper(II)
%J Australian Journal of Chemistry
%D 1995/04/01
%V 48
%N 4
%P 771-781
%K 
%R https://doi.org/10.1071/CH9950771
%U https://www.publish.csiro.au/paper/CH9950771 
%X The crystal structure of bis(2-aminopyridinum) tetrachlorocuprate (II) has been determined by single-crystal X-ray diffraction. The triclinic unit cell, space group P&#299;, contains a single formula unit in the asymmetric unit. The CuCl42- ions occur as isolated groups having a highly flattened tetrahedral geometry. The chloride ions are hydrogen-bonded to both nitrogen atoms of the cation, and the influence of this upon the geometry of the copper(II) complex is discussed. The low-temperature single-crystal electronic spectrum of the compound is reported, and the intensities and energies of the d-d transitions are related to the degree of distortion of the CuCl42- ion. The electronic spectrum of a crystal of bis (2-aminopyrimidinium) tetrachlorocopper (II), which contains a tetragonally elongated octahedral complex in which the cation forms long axial bonds to the copper(II) ion, was also measured for comparison. Angular overlap metal-ligand bonding parameters are derived for the two compounds, and discussed in terms of the different geometries of the complexes. 
