Problem 36 - Chemistry in 30 days

Question

A square planar complex is formed by hybridization of which atomic orbitals? (a) \(\mathrm{s}, \boldsymbol{P}_{\mathrm{N}} \boldsymbol{P}_{\mathrm{y}}, \boldsymbol{P}_{4}\) (b) \(s, p_{x} p_{x} \cdot d_{x^{3}}-y^{2}\) (c) \(\mathrm{s} \mathrm{Px} \mathrm{Py} \mathrm{dz} 2\) (d) \(s p x p z d x y\)

Step-by-Step Solution

Answer

Option (d) is correct: the dsp² hybridization involves s, p_x, p_z, and d_xy orbitals.

Step 1: Understand the Geometry of Square Planar Complexes

A square planar complex has a central atom surrounded by ligand atoms forming the vertices of a square in a single plane. This requires specific hybridization to allow for the square planar shape.

Step 2: Identify the Required Hybridization for Square Planar Shape

In a square planar complex, the hybridization involved is usually dsp². This means one d orbital, one s orbital, and two p orbitals hybridize to form the shape.

Step 3: Determine the Suitable Atomic Orbitals

The dsp² hybridization involves the following atomic orbitals: one s orbital, two p orbitals (such as px and py), and one d orbital (commonly dsp² involves the dxy orbital).

Step 4: Match the Options with dsp² Hybridization

Reviewing the options: Option (d) uses the orbital set `s p_x p_z d_{xy}`. It matches the dsp² hybridization pattern because `d_{xy}` is a d orbital, `s` is an s orbital, and `p_x` and `p_z` correspond to the p orbitals.

Key Concepts

Hybridization

In chemistry, hybridization is a concept used to describe the mixing of atomic orbitals to form new hybrid orbitals. These hybrid orbitals have different shapes and orientations compared to the original atomic orbitals.

The purpose of hybridization is to explain molecular geometry and chemical bonding in a way that aligns with experimental observations. For example, in methane (CH extsubscript{4}), the central carbon atom undergoes sp9 hybridization to form four equivalent sp9 hybrid orbitals.

These orbitals form sigma bonds with hydrogen atoms, resulting in a tetrahedral shape. Thus, hybridization helps predict molecular structure and bond angles.

Key points about hybridization include:

• It involves the combination of s, p, and sometimes d orbitals.
• It results in hybrid orbitals that are better suited for bonding than the component atomic orbitals.
• It helps explain the shape and geometry of molecules.

dsp² Hybridization

The dsp8 hybridization is a specific type of hybridization necessary for forming square planar complexes.

In this type of hybridization, one d orbital, one s orbital, and two p orbitals mix to create four hybrid orbitals that are used for bonding with ligands in a planar square shape.

This arrangement maximizes the distance between bonded ligands, reducing repulsive interactions and stabilizing the square planar geometry typically observed in complexes of transition metals, such as platinum(II) and gold(III).

Important aspects of dsp8 hybridization include:

• It involves d9y orbitals along with px and py beside an s orbital.
• It is common in transition metals with d9y orbitals available for bonding.
• It forms a square planar shape, distinctive from tetrahedral or octahedral geometries.

Atomic Orbitals

Atomic orbitals are regions in an atom where there is a high probability of finding an electron. These orbitals are described by quantum numbers and have specific shapes and orientations.

Fundamental atomic orbitals include s, p, d, and f orbitals, each defined by the principal quantum number (n) and the azimuthal quantum number (l).

For example, an s orbital is spherical, while p orbitals are dumbbell-shaped.

When atoms approach each other to form molecules, their atomic orbitals can overlap to form molecular orbitals, or they can mix to create hybrid orbitals through hybridization.

Key points about atomic orbitals:

• s orbitals are spherical and can hold up to 2 electrons.
• p orbitals are shaped like dumbbells and are oriented along the x, y, and z axes.
• d and f orbitals have more complex shapes and are involved in bonding in transition metals and lanthanides/actinides.

Ligands

Ligands are ions or molecules that can donate a pair of electrons to a central atom to form a coordination complex.

They are crucial in chemistry for forming complexes, especially with transition metals, which often exhibit multiple oxidation states and coordination numbers.

Ligands influence the properties and stability of complexes, including their geometry, reactivity, and color.

They can be classified based on:

• The nature of their electron donors, such as neutral (e.g., water, ammonia) or anionic (e.g., chloride, hydroxide).
• The number of binding sites they offer the central atom; for instance, monodentate ligands like chloride (binding through one atom) and bidentate ligands like ethylenediamine (bonding through two atoms).

Ligands play a crucial role in determining the overall structure and function of a complex, impacting everything from its electronic properties to its biological activity.