CoF₆^3- absorbs light in the red region of the spectrum, while Co(NH₃)₆³⁺ absorbs light in the blue region of the spectrum. This difference means that ________ A)the splitting of the d orbitals of the two complexes is nearly identical. B)the value of the crystal field splitting is very small for both complexes. C)the crystal field splitting is larger for the ammonia complex than for the fluoride complex. D)the d_z² and d_x² -_y² orbitals are higher in energy than the d_xy, d_xz, and d_yz orbitals in CoF₆^3- and just the opposite splitting order for Co(NH₃)₆³⁺. E)the d_z² and d_x² - _y² orbitals are lower in energy than the d_xy, d_xz, and d_yz orbitals in CoF₆^3- and just the opposite splitting order for Co(NH₃)₆³⁺.

Question

Quizplus · Accepted Answer

The absorption of light in different regions of the spectrum (red vs. blue) indicates a difference in the energy required to promote electrons between d orbitals, which is directly related to the crystal field splitting energy. A larger splitting results in absorption of light with higher energy (shorter wavelength), so the ammonia complex, which absorbs in the blue region, has a larger crystal field splitting than the fluoride complex, which absorbs in the red region.

CoF63- Absorbs Light in the Red Region of the Spectrum

CoF₆^3- Absorbs Light in the Red Region of the Spectrum