The lowest energy d-d transition in the Cr(III) complexes varies in the order:
1
\(CrCl_6^{3-}\) < \(Cr(H_2O)_6^{3+}\) < \(Cr(en)_3^{3+}\) < \(Cr(CN)_6^{3-}\)
2
\(CrCl_6^{3-}\) < \(Cr(en)_3^{3+}\) < \(Cr(H_2O)_6^{3+}\) < \(Cr(CN)_6^{3-}\)
3
\(Cr(CN)_6^{3-}\) < \(CrCl_6^{3-}\) < \(Cr(H_2O)_6^{3+}\) < \(Cr(en)_3^{3+}\)
4
\(Cr(H_2O)_6^{3+}\) < \(Cr(en)_3^{3+}\) < \(CrCl_6^{3-}\) < \(Cr(CN)_6^{3-}\)
5
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