Color and Magnetism in Coordination Chemistry;

Chapter , Problem 54E

(choose chapter or problem)

The color and wavelength of the absorption maximum for \(\left[\mathrm{Ni}\left(\mathrm{H}_{2} \mathrm{O}\right)^{6}\right]^{2+},\left[\mathrm{Ni}\left(\mathrm{H}_{3} \mathrm{O}\right)_{6}\right]^{2+}\), and \(\left[N i(e n)_{3}\right]^{2+}\) are given in Figure 23.30. The absorption maximum for the \(\left[\text { Ni }(\text { bipy })_{3}\right]^{2+}\) ion occurs at about 520 nm. (a) What color would you expect for the \(\left[\text { Ni }(\text { bipy })_{3}\right]^{2+}\) ion? (b) Based on these data, where would you put bipy in the spectrochemical series?

If you were to use a ligand L that was a stronger field ligand than ethylenediamine, what color would you expect the \(\left[N i L_{6}\right]^{2+}\) complex ion to have?

▲ Figure 23.30 Effect of ligand on crystal-field splitting. The greater the crystal-field strength of the ligand, the greater the energy gap  it causes between the \(t_{2}\) and e sets of the metal ion’s orbitals. This shifts the wavelength of the absorption maximum to shorter values.

Equation transcription:

Text transcription:

[{Ni}({H}_{2}{O})^{6}]^{2+},[{Ni}({H}_{3}{O})_{6}]^{2+}

[N i(e n)_{3}]^{2+}

[{ Ni }({ bipy })_{3}]^{2+}

[N i L_{6}]^{2+}

t_{2}