How many unpaired electrons are there in the tetrahedral complex ion [FeCl₄]^-? A)1 B)2 C)3 D)4 E)5

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In the tetrahedral complex ion [FeCl4]^-1, iron (Fe) is in the +3 oxidation state (Fe^3+). The electronic configuration of Fe^3+ is [Ar]3d^5. In a tetrahedral field, the d-orbitals do not split into t2g and eg levels as they do in an octahedral field, but there is still a splitting into two sets, with three orbitals at a lower energy and two at a higher energy. However, because there are 5 unpaired electrons in Fe^3+ and the splitting is generally less significant in tetrahedral complexes (not enough to cause pairing of electrons), all five electrons remain unpaired.

How Many Unpaired Electrons Are There in the Tetrahedral Complex