What is a representative orbital-filling diagram for the cobalt ion in the low spin complex of [Co(CN)₆]^3-? A)(

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Quizplus · Accepted Answer

The cobalt ion in the low spin complex [Co(CN)₆]^3- is in the +3 oxidation state (the sum of the oxidation states of CN- and S is -4, so the oxidation state of Co must be +3 to balance the charge of the compound). Since the complex is low spin, we know that the electrons will fill the t2g orbitals before the eg orbitals. The orbital-filling diagram for Co(III) in a low spin complex is as follows: t2g: ↑↓ ↑↓ ↑↓ eg: The complex has six ligands (four CN- and two S2-) which are all strong field ligands that will cause a large splitting of the d orbitals. Therefore, the t2g orbitals will be filled first with six electrons, leaving the eg orbitals empty. The diagram in choice B matches this configuration.

What Is a Representative Orbital-Filling Diagram for the Cobalt Ion