What is molecular orbital?

What Does molecular orbital Mean

The first step that we are going to take in order to know the meaning of the term molecular orbital is to discover the etymological origin of the two words that give it its shape:

-Orbital, first of all, it derives from Latin. More specifically, we can state that it is the result of the sum of two lexical components: the word "orbit", which can be translated as "circular motion path", and the suffix "-al".

-Molecular, secondly, it also comes from Latin. In your case, it emanates from “molecularis”, which is equivalent to “relative to the minimum amount of a substance”. This Latin word was formed by uniting three lexical components: the noun “moles”, which means “mass”; the suffix “-culum”, which is used to indicate a diminutive, and the suffix “-ar”, which is equivalent to “relative to”.

To understand the idea of molecular orbital , it is first necessary to define other terms that are indispensable for understanding the notion. As a starting point, it must be clear that an atom is a particle that cannot be divided by a chemical method.

Atoms exhibit a nucleus that is surrounded by electrons : that is, elementary particles that have a negative electrical charge. Electrons, therefore, rotate around the atomic nucleus with wave motions.
The area around the nucleus where there is a high probability of finding an electron is called an atomic orbital . It is, therefore, a space around the nucleus in which electrons are very likely to be found.
Now we can focus on the definition of molecular orbital . This is the name given to the combination of the atomic orbitals of two atoms that are linked .
A molecular orbital is formed by a set of atomic orbitals in an atom of a molecule . The electronic configuration of each molecule depends on its molecular orbitals.
Molecular orbitals are often linked to mathematical functions that reflect how electrons behave in molecules from the perspective of quantum chemistry . Mathematical functions allow describing the wave behavior of electrons.
In other words, a molecular orbital is a spatial region that has the electron density indicated by mathematical functions. These functions , in turn, are used to calculate physical and chemical properties.
It is important to mention that molecular orbitals can be binding (they have less energy than atomic orbitals that allow their creation and are in a situation of attraction) or anti-bonding (they have higher energy than each atomic orbital and are in a state of repulsion).

In addition to all the above, we cannot ignore either that molecular orbitals have the peculiarity that they can charge or fill electrons in three different ways. Specifically, through these:

-Through the Pauli exclusion principle. In this step it is indicated that the aforementioned orbitals when created will be able to host a maximum of two electrons.

-By a clear decreasing order of the energy level. In this case, it must be established that the bonding molecular orbitals will be charged with electrons earlier than the antibonding orbitals.

-Through Hund's rule of maximum duplicity. This is the option that is taken when what is sought is to obtain orbitals that respond to the name of half-full.

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