Chromium complexes, absorption table

Tables 1 and 2 gives the numerical data for a series of vanadium (II), chromium (III), manganese (IV), molybdenum (III), rhenium (IV), iridium (VI), cobalt (II), and nickel (II) complexes. The first spin-allowed absorption band, caused by an internal transition in the partly filled shell, has the wavenumber equal to A. If spin-forbidden transitions are superposed on this band, a certain distortion from the usual shape of Gaussian error curve can be observed, and one takes the centre of gravity of intensity as the corrected wavenumber ai. One has to be careful not to confuse electron transfer or other strong bands with the internal transitions discussed here. Obviously, one has also to watch for absorption due to other coloured species, produced e. g. by oxidation or hydrolysis of the solutions. In the case of certain octahedral nickel (II), and nearly all tetrahedral cobalt (II) complexes, the first band has not actually been...

Large numbers of mononuclear, octahedral Cr(III) complexes are known with magnetic moments close to the spin-only value of 3.87 /tb (Table 20.7) the electronic spectra of octahedral d complexes contain three absorptions due to d-d transitions (see Figure 20.18). Selected examples of octahedral chromium(III) complexes are [Cr(acac)3], [Cr(ox)3] ,... 

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