Top topic this week
Back to FAQs
Related FAQs
Frequently Asked Question
Questions asked by users might not always be phrased in the clearest way.
Choose the coordination complex from below that would present with the peak of shortest wavelength: [crcl6]3- [cr(h2o)6]3+ [cr(en)3]3+ [ni(h2o)6]2+
Accepted Answer
The coordination complex with the shortest wavelength peak is [Cr(en)3]3+. Here's why:
Crystal Field Theory: The color of a coordination complex arises from the absorption of light, which causes an electron to jump from a lower energy d-orbital to a higher energy d-orbital. The energy difference between these orbitals is called the crystal field splitting energy (Δ). A larger Δ corresponds to higher energy light absorption (shorter wavelength).
Ligand Strength: The strength of the ligands surrounding the central metal ion determines the size of Δ. Strong-field ligands, like ethylenediamine (en), cause a larger splitting. Weak-field ligands, like chloride (Cl-) and water (H2O), cause a smaller splitting.
Metal Ion: The identity of the metal ion also influences Δ. Chromium(III) (Cr3+) generally has a larger Δ than nickel(II) (Ni2+).
In summary: [Cr(en)3]3+ has the strongest-field ligands (en) and the metal ion with a larger Δ (Cr3+), leading to the highest energy absorption and shortest wavelength of light.
Articles you might like