Consider two complexes: (I) [Fe(CN)₆]^4-, and (II) [Fe(H₂O)₆]²⁺. In view of the spectrochemical series, which one of the following sets of predictions is most likely correct? Spectrochemical Series A)I is low spin, II is high spin, and II absorbs light at the shorter wavelength. B)I is low spin, II is high spin, and I absorbs light at the shorter wavelength. C)I is high spin, II is low spin, and I absorbs light at the shorter wavelength. D)Both have six d electrons, so both are high spin. E)Both have six d electrons, so both are low spin.

Question

Quizplus · Accepted Answer

According to the spectrochemical series, cyanide (CN-) is a strong field ligand and favors low spin configurations, while H₂O (thiolate) is a weak field ligand and favors high spin configurations. Therefore, complex I, which contains CN- ligands, is more likely to be low spin, while complex II, which contains thiolate ligands, is more likely to be high spin. Additionally, low spin complexes absorb light at longer wavelengths, while high spin complexes absorb light at shorter wavelengths. Therefore, I is expected to absorb light at longer wavelengths, while II is expected to absorb light at shorter wavelengths. Thus, the correct answer is B.

Consider Two Complexes: (I) [Fe(CN)6]4-, and (II) [Fe(H2O)6]2+

Consider Two Complexes: (I) [Fe(CN)₆]^4-, and (II) [Fe(H₂O)₆]²⁺