Question

Discuss the structure of \(\mathrm{Re}_{2} \mathrm{Cl}_{8}\) and justify for its bond order using molecular orbital theory.

Short answer

The compound \(\mathrm{Re}_{2} \mathrm{Cl}_{8}\) has a bond order of 6.

Step-by-step solution

Identify the Structure

The compound \(\mathrm{Re}_{2} \mathrm{Cl}_{8}\) has a cubic structure of chlorine atoms around rhenium metal atoms. Each Re atom is bonded to 4 Cl atoms.

Apply Molecular Orbital Theory

Molecular Orbital theory suggests that atomic orbitals merge to form molecular orbitals, which can be filled with electrons. For \(\mathrm{Re}_{2} \mathrm{Cl}_{8}\), since there are two Re atoms, the orbitals will be doubled. There are 5 atomic orbitals for Re d-orbitals so it will generate 10 molecular orbitals.

Calculate Bond Order

The bond order can be calculated using the formula: Bond Order = (No. of electrons in bonding orbitals - No. of electrons in anti-bonding orbitals)/2 . For \(\mathrm{Re}_{2} \mathrm{Cl}_{8}\), all 12 electrons from the \(5d\) orbital of each Re atom are in bonding orbitals with no electron in antibonding orbitals. So, the bond order = \(12-0)/2 = 6.

Key concepts

Bond Order

Bond order is an important concept in molecular chemistry, helping us determine the strength and stability of a bond between two atoms. Using Molecular Orbital Theory, bond order can provide insights into how electrons are shared or transferred in a chemical composition. It's calculated using the formula: \[ \text{Bond Order} = \frac{(\text{Number of electrons in bonding orbitals} - \text{Number of electrons in antibonding orbitals})}{2} \] For \( \mathrm{Re}_{2} \mathrm{Cl}_{8} \), the bond order calculation is based on the number of electrons present in these orbitals. As we learn, \( 12 \) electrons are in bonding orbitals and none are in antibonding orbitals, leading to a bond order of \( 6 \). A higher bond order signifies stronger bonding and often more stability in the compound.

Re2Cl8 structure

Understanding the structure of \( \mathrm{Re}_{2} \mathrm{Cl}_{8} \) provides a visual framework for chemical interactions. This compound features a cubic surrounding of chlorine atoms around the rhenium atoms. Each rhenium atom is bonded with four chlorine atoms. This arrangement indicates strong coordination bonds typical in inorganic chemistry structures. Such geometric arrangements play a vital role in determining the physical and chemical properties of the compound. The shared bonding leads to a stable lattice due to optimal electron distribution and satisfies the electron configuration of the participating atoms. Recognizing these bond arrangements helps predict how structures behave in different reactions.

Molecular Orbitals

Molecular orbitals arise when atomic orbitals overlap and interact, creating new orbitals that belong to the entire molecule rather than to just one atom. According to Molecular Orbital Theory, these new orbitals can accommodate electrons from the interacting atomic orbitals. In the case of \( \mathrm{Re}_{2} \mathrm{Cl}_{8} \), 10 molecular orbitals are formed due to the overlapping of the \( 5d \) orbitals from each of the two Re atoms. These molecular orbitals are crucial in understanding electron distribution and energy levels within the molecule. This model supports the concept that electrons in molecules can be tracked in terms of energy states, explaining electron delocalization and bonding strength.

Inorganic Chemistry

Inorganic chemistry focuses on compounds that aren't primarily hydrocarbons. \( \mathrm{Re}_{2} \mathrm{Cl}_{8} \) is an inorganic compound, highlighting its inclusion in this scientific field. Inorganic compounds often involve metals like rhenium and nonmetals like chlorine, resulting in diverse combinations and structures. This field goes beyond simple compositions, considering aspects such as coordination chemistry and crystallography. With elements from across the periodic table, inorganic chemistry explores bonding, electron configurations, and interactions that do not depend on carbon frameworks. It allows for understanding a universe of substances that underpin many industrial and biotechnological processes.