An extended X-ray absorption fine structure study of penta-amminecopper(II) bis(tetrafluoroborate): Evidence for five equal bond lengths

The extended X-ray absorption fine structure spectra of powered [Cu(NH3)5][BF4]2 have been measured at room temperature and at 77 K using synchrotron radiation. Standard Fourier-transform and least-squares fitting methods utilising [Cu(en)2][BF4]2 (en = ethylenediamine) as a model complex for extracting amplitude and phase parameters for Cu-N bonds demonstrate that in each case only a single shell is present about the metal ion, i.e. all five Cu-N bonds are of equal length.