Question

Draw the structure of the following coordination compounds and determine the oxidation state, da nt electronic configuration, ( t2 gm eg” Or emt2" configuration and the spin only magnetic moment of the metal atom.

[Ni(en)3]2+ , en = 1,2-diaminoethane

Answer 1

Answer on Question #77158, Chemistry / Inorganic Chemistry

Draw the structure of the following coordination compounds and determine the oxidation state, da nt electronic configuration, ( t2 gm eg" Or emt2" configuration and the spin only magnetic moment of the metal atom.

[Ni(en)3]2+, en = 1,2-diaminoethane

Solution

Structure of $\left[\mathrm{Ni}(\mathrm{en})_{3}\right]^{2+}$, en = 1,2-diaminoethane

The electron configuration of Nickel is: [Ar] $3d^{8}4s^{2}$

Oxidation state of Nickel in $\left[\mathrm{Ni}(\mathrm{en})_{3}\right]^{2+}$ is $\mathrm{Ni}^{2+}$, as en ligands are neutral.

Atom of Ni looses two electrons to become an ion $\mathrm{Ni}^{2+}$ therefore it's electronic configuration is $d^{8}$.

The complex $\left[\mathrm{Ni}(\mathrm{en})_{3}\right]^{2+}$ has an octahedral shape, en is a strong field ligand, but the appropriate crystal field diagram shows that only one configuration is possible irrespective of the strength of the ligand field.

Splitting d-orbital diagram of $\left[\mathrm{Ni}(\mathrm{en})_{3}\right]^{2+}$ is: $t_{2g}^{6}e_{g}^{2}$

This complex is paramagnetic as it has two lone electrons. To find the spin only magnetic moment of the metal atom we should use the formula, based on the number of unpaired electrons n:

$$\mu_{so} = \sqrt{n(n + 2)}$$

For complex $\left[\mathrm{Ni}(\mathrm{en})_{3}\right]^{2+}$, $\mu_{so} = \sqrt{2(2 + 2)} = \sqrt{8} = 2.83\ \mu_{B}$

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