Coordination Chemistry Quiz

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Questions and Answers

What is the coordination number of the complex [Ni(CN)4] 2−?

4 (correct)

What is the geometry of the complex [Ni(CN)4] 2−?

Trigonal bipyramidal

Tetrahedral

Octahedral

Square planar (correct)

Which statement is true regarding the electronic configuration of Ni in the complex [Ni(CN)4] 2−?

Ni is in the +1 oxidation state.

Ni has only 4 electrons in its outer shell.

Ni is in the +2 oxidation state. (correct)

Ni has unpaired electrons.

What type of hybridization occurs in the complex [Ni(CN)4] 2−?

dsp2 Signup and view all the answers

Which factor contributes to the diamagnetism of the complex [Ni(CN)4] 2−?

Presence of strong field ligands. Signup and view all the answers

Which complex is classified as an outer orbital complex?

[Ni(NH3)6]2+ Signup and view all the answers

What is the hybridization of [Mn(CN)6]3−?

d2sp3 and octahedral Signup and view all the answers

What is the electronic configuration of Mn3+ in [Mn(CN)6]3−?

[Ar]3d4 Signup and view all the answers

How many unpaired electrons are in a d6, low spin, octahedral complex?

0 Signup and view all the answers

Which hybridization corresponds to the octahedral geometry of [Mn(CN)6]3−?

d2sp3 Signup and view all the answers

What is the hybridization of Ni in the complex [Ni(CO)4]?

sp3 Signup and view all the answers

What is the geometry of the complex [Ni(CO)4]?

Tetrahedral Signup and view all the answers

Which statement regarding the oxidation state of Ni in [Ni(CO)4] is correct?

Ni is in a 0 oxidation state. Signup and view all the answers

What type of complex is [PdCl4]2− despite Cl being a weak ligand?

Square planar, diamagnetic, dsp2 hybridized Signup and view all the answers

In the context of coordination compounds, what limitation does VBT have?

It does not explain the color exhibited by coordination compounds. Signup and view all the answers

What type of complex do weak ligands typically form?

Outer orbital complexes Signup and view all the answers

Why does [Mn(CN)6]3- form an inner orbital complex?

Due to strong ligand strength Signup and view all the answers

What is the hybridization involved in the complex [Ni(CN)4]2−?

d2sp3 Signup and view all the answers

What factor affects the crystal field splitting, Δo, in octahedral complexes?

The charge on the metal ion and the nature of ligands Signup and view all the answers

Which ligand would create the most significant crystal field splitting?

CN− Signup and view all the answers

In comparing [Co(NH3)6]3+ and [Co(CN)6]3+, which statement is correct?

Δo is higher for [Co(CN)6]3+ than for [Co(NH3)6]3+ Signup and view all the answers

How does increasing the charge on the metal ion affect Δo?

It increases Δo Signup and view all the answers

Which of the following pairs shows a complex with the higher Δo value for the first complex?

[Rh(H2O)6]3+ and [Co(H2O)6]3+ Signup and view all the answers

What is true regarding weak field ligands?

They decrease crystal field splitting Signup and view all the answers

Which of the following ligands falls lower in the spectrochemical series?

H2O Signup and view all the answers

The crystal field splitting, Δo, is directly influenced by which of the following?

The type of ligands and metal charge Signup and view all the answers

What is the correct order of increasing field strength of ligands to form coordination compounds?

SCN– < F– < C2O42– < CN– Signup and view all the answers

Which complex has the highest Crystal Field Stabilization Energy (CFSE)?

[Co(CN)6]3– Signup and view all the answers

Which of the following complexes will absorb light of minimum wavelength?

[Co(NH3)6]3+ Signup and view all the answers

What is the correct order of the wavelength of light absorbed by [Co(NH3)5Cl]2–, [Co(NH3)5(H2O)]3+, and [Co(NH3)6]3+?

(III) > (II) > (I) Signup and view all the answers

Which ligand is stronger, CN– or H2O?

CN– Signup and view all the answers

Which complex would have the lowest CFSE?

[Co(H2O)6]3+ Signup and view all the answers

Which ligand has the lowest field strength?

SCN– Signup and view all the answers

In coordination complexes, the greater the ligand field strength, what happens to the Crystal Field Stabilization Energy (CFSE)?

CFSE increases Signup and view all the answers

Study Notes

Outer Orbital Complexes

A complex containing a metal ion which uses its outer d-orbitals along with s and p orbitals of valence shell for hybridization is considered an Outer Orbital Complex.
Examples: [Ni(NH3)6]2+

Inner Orbital Complexes

A complex containing a metal ion which uses its inner d-orbitals along with s and p orbitals of valence shell for hybridization is considered an Inner Orbital Complex.
Examples: [Mn(CN)6]3-

Coordination Number

A coordination number refers to the number of ligands directly attached to the metal ion in coordination compounds.
Common Coordination Numbers: 4 and 6
Coordination Number 4 complexes can be either tetrahedral (sp3 hybridization) or square planar (dsp2 hybridization)
Coordination Number 6 complexes are always octahedral (d2sp3 hybridization)

Determining the Coordination Complex Type

The strength of the ligand determines if a complex will be an inner or outer orbital complex.
Strong field ligands (such as CN-, CO) lead to inner orbital complexes.
Weak field ligands (such as Cl-, H2O) lead to outer orbital complexes.

Spectrochemical Series

The Spectrochemical Series arranges ligands by their increasing strength of splitting the d-orbitals, which leads to the formation of higher and lower energy levels, and ultimately the color of the transition metal complexes.
Ligands are ranked based on their ability to attract electrons, leading to higher energy levels, which are essential for the absorption of light and color.
The order of Spectrochemical Series: I– < Br– < SCN– < Cl– < S2– < F– < OH– < C2O42– < H2O < NCS– < EDTA4– < NH3 < en < CN– < CO

Crystal Field Splitting Energy (Δo)

Δo is the energy difference between the two sets of d-orbitals in an octahedral complex.
The strength of the ligand determines the Δo, with stronger ligands producing larger Δo.
Δo is influenced by:
- Charge on the metal ion: Higher charge leads to larger Δo.
- Metal position in the periodic table: Third row transition metals exhibit higher Δo than first row transition metals.
- Ligands: Stronger field ligands, with a greater ability to attract electrons (such as CN-), generate larger Δo.

Crystal Field Stabilization Energy (CFSE)

CFSE is the extra stability gained for a coordination complex due to the splitting of d orbitals in a crystal field caused by surrounding ligands.
CFSE depends on the electronic configuration of the central metal ion and the nature of the ligands, as stronger ligands give larger CFSE.
Larger CFSE indicates greater stability in the complex.
[Co(CN)6]3– has a higher CFSE due to the strong field ligand CN– than [Co(C2O4)3]3–, [Co(H2O)6]3+, and [Co(NH3)6]3+.

Color of Complexes

The color of a transition metal complex is determined by the wavelength of light that it absorbs and the color that is reflected back to the observer.
Stronger ligands lead to increased energy level separation of the d orbitals, and consequently, a shorter wavelength of light is absorbed.
Stronger ligands result in higher CFSE and also cause the absorption of light at a shorter wavelength.

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Description

Test your knowledge on Outer and Inner Orbital Complexes, as well as Coordination Numbers. This quiz will explore the concepts of hybridization in metal complexes and the influence of ligands on their classification. Prepare to delve into the fascinating world of coordination compounds!