All questions of Coordination Chemistry (d block) for Chemistry Exam

The crystal field stabilization energy (CFSE) is the stability that results from placing a transition metal ion in the crystal field generated by a set of ligands. Conversely, the eg orbitals (in the octahedral case) are higher in energy than in the barycenter, so putting electrons in these reduces the amount of CFSE.

Spin paired complex ions are those in which all the electrons are paired up in the same direction, resulting in a diamagnetic complex. Diamagnetic complexes are not attracted to a magnetic field and have a low magnetic moment.

The correct answer is option 'D', [Co(NH3)6]3.

Explanation:
- Coordination number of complex ion = 6
- Oxidation state of central metal ion = +3
- Cobalt has 27 electrons, so [Co(NH3)6]3+ has 24 electrons
- NH3 is a strong field ligand, so it will pair up the electrons in the t2g orbitals before occupying the eg orbitals
- Therefore, all the electrons in the complex ion are paired up in the same direction, resulting in a diamagnetic complex
- Hence, [Co(NH3)6]3+ is a spin paired complex ion

Let's look at the other options:
a) [Cr(NH3)6]3+: Chromium has a d4 configuration, so it has one unpaired electron in the t2g orbitals. Hence, it is a paramagnetic complex.
b) [Cr(CN)6]3-: Cyanide is a strong field ligand, so it will pair up the electrons in the t2g orbitals before occupying the eg orbitals. However, chromium has a d3 configuration, so it will have one unpaired electron in the eg orbitals. Hence, it is a paramagnetic complex.
c) [Fe(C2O4)3]3-: Iron has a d5 configuration, so it has one unpaired electron in the t2g orbitals. Hence, it is a paramagnetic complex.

Though none is the option is fully crrct...but u can say 1 nd 2 is partially crrt

Because pairing energy is more that means electrons are not get paired against the Hund' s rule

Cr(lll) is a d3 system so there are two (n-1)d orbital is availble for hybdsn so it always show d2sp3 hybsn

A particular wavelength is a measure of how strongly a molecule absorbs light at that wavelength. It is usually denoted by the symbol ε (epsilon) and has units of L mol^-1 cm^-1. The molar absorptivity depends on the molecular structure and the electronic transitions that occur when the molecule absorbs light. It is used in the Beer-Lambert law, which relates the concentration of a solution to its absorbance: A = εcl, where A is the absorbance, c is the concentration, and l is the path length of the solution.

The complex which exhibits lowest energy electronic absorption band is [NiCl4]2. This can be explained through the following points:

Explanation:

1. Determining factors for energy of electronic absorption band
The energy of electronic absorption bands depends on various factors such as the nature of the ligand, oxidation state of the metal ion, coordination number, geometry of the complex, and the extent of d-orbital splitting.

2. Comparison of given complexes
Out of the given complexes, [NiCl4]2, [Ni(H2O)6]2, [Ni(CN)4]2, and Ni(CO)4, the complex with the lowest energy of electronic absorption band is [NiCl4]2.

3. Reason for lowest energy in [NiCl4]2
The reason for this can be attributed to the nature of the ligand. Chloride ion being a weak field ligand, it causes less splitting of the d-orbitals of the nickel ion. This results in a lower energy of electronic absorption band as compared to the other complexes where ligands such as water, cyanide, and carbon monoxide cause a greater extent of d-orbital splitting due to their strong field nature.

4. Other factors affecting energy of electronic absorption band
Although the oxidation state of the metal ion, coordination number, and geometry of the complex also affect the energy of electronic absorption bands, in this case, the nature of the ligand is the primary determining factor.

Conclusion:
Thus, [NiCl4]2 is the complex that exhibits the lowest energy of electronic absorption band due to the weak field nature of the chloride ligand causing less splitting of the d-orbitals of the nickel ion.

Explanation:
Mn3O4 is a mixed oxide of Mn2+ and Mn3+. It has both tetrahedral and octahedral sites. The ratio of Mn2+ and Mn3+ ions in these sites is different.

- Tetrahedral sites: In Mn3O4, there are 8 tetrahedral sites. The Mn2+ ions occupy the tetrahedral sites in a 1:1 ratio with oxygen ions. So, there are 8 Mn2+ ions in the tetrahedral sites.
- Octahedral sites: In Mn3O4, there are 16 octahedral sites. The Mn3+ ions occupy the octahedral sites in a 2:1 ratio with oxygen ions. So, there are 32 Mn3+ ions in the octahedral sites.

Therefore, the number of manganese ions in tetrahedral and octahedral sites, respectively in Mn3O4 are one Mn2+ and two Mn3+. Hence, the correct answer is option A.

John teller distortion occur only in those compound in which unsymmetrical filling of t2g and eg orbital takes place ..I1st compound had d5 configuration n are symmetrically filled so no jtd.2nd has d4 configuration n high spin complex so its one eg orbital is unsymetrically filled resulting jtd
Option c has d3 configuration and as H20 is weak field ligand so its t2g orbital is symmetrically filled resultin no jtd
Last one has d6 configuration is low spin complex of iron due to strong field nature of pi acceptor ligand cNSo its teg orbital is symmetrically filled reasulting no jtdSo only option 2nd is correct

Option b is correct. In all cases cr is in +3 oxidation state. thus d3 system. irrespective of nature of ligand( weak or strong) it should have same cfse

To calculate the number of moles of CoCl3 in the solution, we need to divide the mass of CoCl3 by its molar mass.

Molar mass of CoCl3 = 129.84 g/mol

Number of moles of CoCl3 = 2.675 g / 129.84 g/mol = 0.0206 mol

Therefore, the solution contains 0.0206 mol of CoCl3.

I'm sorry, but you haven't provided a list of solvated metals for me to arrange. Could you please provide the list so that I can assist you further?

Explanation:

For d5s1 configuration, since s=1/2, the total spin can range from 5/2 to 1/2. The total angular momentum can range from 4 to 0.

For d5 configuration, since there are 5 electrons with s=1/2, the total spin can range from 5/2 to 1/2. The total angular momentum can range from 5 to 0.

To determine the ground state term symbol, we need to find the combination of spin and angular momentum that gives the lowest energy.

For d5s1 configuration:

- The lowest spin state is when all electrons are paired, giving a total spin of S=0.
- The lowest angular momentum state is when all electrons occupy the same d orbital, giving a total angular momentum of L=2.
- The ground state term symbol is then 3S, since S=0 and L=2.

For d5 configuration:

- The lowest spin state is when all electrons are paired, giving a total spin of S=0.
- The lowest angular momentum state is when all electrons occupy the same d orbital, giving a total angular momentum of L=5.
- The ground state term symbol is then 6S, since S=0 and L=5.

Therefore, the correct answer is option C, 7S and 6S.

-, [FeCl6]3-
c)KMnO4, Fe2O3
d)MnSO4, FeCO3

Answer: b) [MnO4]-, [FeCl6]3-

Introduction:
The square planar geometry is a type of molecular geometry that describes the arrangement of atoms in a molecule. In this geometry, the central atom is surrounded by four ligands that are arranged in a square plane around it. The square planar geometry is commonly observed in transition metal complexes and some organic molecules.

Explanation:
The correct answer to the question is option 'A', which states that the square planar geometry is based on the Z-exclusion principle. Let's understand why this is the correct answer.

Z-exclusion principle:
The Z-exclusion principle, also known as the 18-electron rule, is a concept in chemistry that describes the stability of transition metal complexes based on the number of valence electrons present. According to this principle, stable transition metal complexes tend to have 18 valence electrons surrounding the central metal atom.

Electronic configuration:
In the square planar geometry, the central atom is typically a transition metal, which has d orbitals available for bonding. The electronic configuration of transition metals allows them to form coordination complexes by donating and accepting electron pairs.

Ligands in square planar geometry:
In a square planar geometry, the central atom is surrounded by four ligands arranged in a square plane. These ligands can be either negatively charged (anions) or neutral molecules. The ligands form coordinate covalent bonds with the central atom by donating a pair of electrons.

Electronegativity of ligands:
The Z-exclusion principle is based on the fact that the ligands in a transition metal complex are negatively charged or neutral. This is because ligands with positive charges would be highly electronegative and would not form stable bonds with the metal atom. Hence, the Z-exclusion principle ensures that the ligands are electroneutral or negatively charged to maintain stability.

Conclusion:
In conclusion, the square planar geometry is based on the Z-exclusion principle, which describes the stability of transition metal complexes based on the number of valence electrons present. This principle ensures that the ligands surrounding the central metal atom in a square planar geometry are electroneutral or negatively charged, maintaining stability in the complex.

A) K4[Fe(CN)6] is a low spin complex because Fe(II) has a d6 configuration with electrons pairing up in the lower energy d orbitals before pairing in the higher energy orbitals.

b) [PtCl4]2- is a high spin complex because Pt(II) has a d8 configuration with unpaired electrons that occupy the higher energy orbitals.

D3 and d8 will give this cfse value
both does not have low or high spin.
same for strong and weak ligand.
and have 2 or 3 unpaired electron

UV Visible Spectroscopy as a Method to Determine CFSE of Transition Metal Complexes

UV visible spectroscopy is a powerful technique used to determine the crystal field splitting energy (CFSE) of transition metal complexes. This method involves the use of light to study the electronic transitions in the metal-ligand bond, which provides valuable information about the CFSE and the electronic structure of the complex.

The principle of UV-visible spectroscopy is based on the fact that when light is absorbed by a molecule, it promotes an electron from a lower energy level to a higher energy level, resulting in the formation of an excited state. The energy difference between the ground state and the excited state is related to the CFSE of the complex.

Steps Involved in Determining CFSE of Transition Metal Complexes using UV-Visible Spectroscopy:

1. Preparation of Samples: The first step in determining CFSE of a transition metal complex using UV-Visible spectroscopy is the preparation of the sample. The sample must be carefully prepared to ensure that it is homogeneous and free from any impurities.

2. Measurement of Absorbance: Once the sample is prepared, the UV-Visible spectrum of the complex is obtained. The spectrum is obtained by measuring the absorbance of the sample at different wavelengths of light. The absorbance is then plotted against the wavelength to produce a spectrum.

3. Analysis of Spectrum: The spectrum is then analyzed to determine the CFSE of the complex. The CFSE is determined from the energy difference between the ground state and the excited state. The lower the energy difference, the higher the CFSE.

4. Comparison with Theoretical Values: The value obtained for the CFSE is then compared with the theoretical value to determine the accuracy of the measurement.

Advantages of Using UV-Visible Spectroscopy to Determine CFSE:

1. Non-destructive: UV-Visible spectroscopy is a non-destructive method, which means that the sample can be used for further analysis.

2. High sensitivity: UV-Visible spectroscopy is a highly sensitive technique, which means that it can detect even small changes in the electronic structure of the complex.

3. Easy to use: UV-Visible spectroscopy is a relatively simple and easy-to-use technique, which makes it accessible to a wide range of researchers.

Conclusion:

In conclusion, UV-Visible spectroscopy is a powerful technique that can be used to determine the CFSE of transition metal complexes. This method provides valuable information about the electronic structure of the complex, which can be used to design new materials with specific properties.