For each of the following, (i) give the systematic name of...

For each of the following, (i) give the systematic name of the compound and specify the oxidation state of the transition metal, (ii) draw a crystal field energy-level diagram and assign the electrons to orbitals, (iii) indicate whether the complex is high-spin or low-spin (for $d^{4}-d^{7}$ complexes), and (iv) specify the number of unpaired electrons. (a) $\left(\mathrm{NH}_{4}\right)\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]\left(\mathrm{SO}_{4}\right)_{2}$ (b) $\mathrm{Mo}(\mathrm{CO})_{6}$($CO$ is a strong-field ligand) (c) $\left[\mathrm{Ni}\left(\mathrm{NH}_{3}\right)_{4}\left(\mathrm{H}_{2} \mathrm{O}\right)_{2}\right]\left(\mathrm{NO}_{3}\right)_{2}$ (d) $\mathrm{K}_{4}\left[\mathrm{Os}(\mathrm{CN})_{6}\right]$ (e) $\left[\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{4}\right]\left(\mathrm{ClO}_{4}\right)_{2}$ (f) $\mathrm{Na}_{2}\left[\mathrm{Fe}(\mathrm{CO})_{4}\right]$

For each of the following, (i) give the systematic name of the compound and specify the oxidation state of the transition metal, (ii) draw a crystal field energy-level diagram and assign the electrons to orbitals, (iii) indicate whether the complex is high-spin or low-spin (for $d^{4}-d^{7}$ complexes), and (iv) specify the number of unpaired electrons.

(a) $\left(\mathrm{NH}_{4}\right)\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]\left(\mathrm{SO}_{4}\right)_{2}$
(b) $\mathrm{Mo}(\mathrm{CO})_{6}$($CO$ is a strong-field ligand)
(c) $\left[\mathrm{Ni}\left(\mathrm{NH}_{3}\right)_{4}\left(\mathrm{H}_{2} \mathrm{O}\right)_{2}\right]\left(\mathrm{NO}_{3}\right)_{2}$
(d) $\mathrm{K}_{4}\left[\mathrm{Os}(\mathrm{CN})_{6}\right]$
(e) $\left[\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{4}\right]\left(\mathrm{ClO}_{4}\right)_{2}$
(f) $\mathrm{Na}_{2}\left[\mathrm{Fe}(\mathrm{CO})_{4}\right]$

Key Concepts

Magnetic Properties of Coordination Complexes

The magnetic behavior of a coordination complex is directly determined by the number of unpaired electrons present. Complexes with more unpaired electrons exhibit paramagnetism, while those with all paired electrons are diamagnetic. Understanding the electron distribution in the split d-orbitals is therefore key to predicting and explaining these magnetic properties.

High-Spin vs. Low-Spin Complexes

The high-spin and low-spin designations refer to the electron configuration in the split d-orbitals of the metal ion, especially in complexes with d^4 to d^7 electron counts. Whether a complex is high-spin or low-spin depends on the strength of the ligand field relative to the electron pairing energy (as described by the spectrochemical series), which in turn affects the number of unpaired electrons.

Crystal Field Splitting Diagrams

These diagrams visually represent the splitting of the metal ion's d-orbitals under the influence of a ligand field. They help in assigning electrons to the appropriate orbitals based on the energy levels, and they are essential in predicting the electronic configuration, stability, and overall behavior of the complex.

Crystal Field Theory

Crystal field theory explains how the degenerate d-orbitals of a transition metal ion split into different energy levels when surrounded by a set of ligands. This theory provides a model to understand the electronic structure, colors, and magnetic properties of coordination compounds by considering the electrostatic interactions between the metal and the ligands.

Oxidation State Determination

Determining the oxidation state of the transition metal in a complex is done by considering the charges of all the ligands and any counterions present. This calculation is crucial because the oxidation state influences the electronic configuration, chemical reactivity, and properties of the metal center within a coordination complex.

Coordination Compound Nomenclature

This concept involves the systematic naming of coordination compounds following IUPAC rules. It includes identifying the central metal atom, its oxidation state, and the type, number, and order of the ligands attached to it, as well as indicating the overall charge of the complex. Proper nomenclature is essential for accurately communicating the structure and composition of these compounds.

Transcript

00:01 So in this question we find out the oxidation state and name of the following complexes and also draw the crystal field energy level diagram and then find out the number of unpaired electron in the following complexes.

00:14 So our first complex is chromium complex that is nh4 cr h2o6 so4 twice.

00:25 So the name of this complex is ammonium hexa so we can write ammonium hexa quackromium hexa hexa aqua chromium three sulfate chromium chromium three sulfate so that means the oxidation state of chromium here is plus three and crystal -filled energy level diagram for this octahedral complexes so here one two and here one two three so now we can fill the electron in these orbitals so here one 2, 3.

01:08 So that means there is 3 unpaired electron is present in this complex.

01:18 Now part b of the question is similarly, part b of the question is the complex is given is malibidinum carbonyl 6.

01:26 So the name of this complex is hexa carbonyl, hexacarbonile, molybidum and oxidation state here is 0.

01:43 That means molybidum oxidation state is 0.

01:46 So we can make a crystal field energy level diagram for this octahedral complexes.

01:54 So here 1, 2, 3, 4, 5, 6.

01:57 So that means this is the low spin complex and there is no unpaired electron.

02:05 There is no unpaired electrons are present in this complex because we can see all the electrons are paired in this complex.

02:14 So there is no unpaired electron present in this complex.

02:19 Now next element is, next complex is we can see this is nickel complex.

02:27 So that is nickel, nh3, 4, water twice.

02:35 And then this is no3 twice.

02:41 So the name of this complex is tetraamine.

02:44 So we can write tetraamine di aqua di aqua nickel to nitrate nickel to nitrate because here oxidation state of nickel is plus two so that that mean nickel in plus two...

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