Crystal Field Splitting — Visual Comparison

Crystal Field Splitting: Octahedral vs Tetrahedral Octahedral [$ML_{6}$] E eg ($dx^{2}$-$y^{2}$, $dz^{2}$) t2g (dxy, dxz, dyz) +0.6$\Delta o$ −0.4$\Delta o$ $\Delta o$ Tetrahedral [$ML_{4}$] E t2 (dxy, dxz, dyz) e ($dz^{2}$, $dx^{2}$-$y^{2}$) +0.27$\Delta o$ −0.18$\Delta o$ $\Delta t$ $\Delta t$ = (4/9)$\Delta o$ ≈ 0.44 $\Delta o$ → Tetrahedral splitting is much SMALLER than octahedral

The figure above shows the contrast between octahedral (left: t_{2}g lower, eg higher, gap = $\Delta o$) and tetrahedral (right: e lower, t_{2} higher, gap = $\Delta t$ ≈ 4/9 $\Delta o$) crystal field splitting patterns.

Flow: How Ligand Identity Determines Observable Properties

Comparison Table: Lanthanoids vs Actinoids

Cisplatin Structure (Wikimedia)

The cis geometry places both $NH_{3}$ groups on the same side and both $Cl^{-}$ groups on the same side. After hydrolysis of $Cl^{-}$ inside the cell, the two resulting reactive sites are geometrically compatible with binding to adjacent guanine bases on the same DNA strand (intrastrand crosslink, ~90° separation), blocking replication and triggering apoptosis.

Summary Table: $KMnO_{4}$ Reactions