Determine the number of unpaired electrons in the octahedral coordination complex [fex6]3–, where x = any halide.

Unpaired electron is the electron, that occupies the a place in orbital without the pair of electron. The number of unpaired electron in 3d sub shell of octahedral coordination complex is 3.

The given octahedral coordination complex in the problem is

Here, is the halogen.

Unpaired electron is the electron, that occupies the a place in orbital without the pair of electron.

In the given complex ion +3 oxidation state (iron) represents in,

As the unpaired electron in 3d sub shell is 3.

Hence the number of unpaired electron in 3d sub shell of octahedral coordination complex is 3.

Learn more about the unpaired electron here;link

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