Name: covalent bond overlap and orbital hybridization
Uploaded: 2025-05-22T09:05:33.000Z
Duration: 2 min 38 s
Channel: JoVE

La teoría del enlace de valencia propone que un enlace químico resulta a través de una superposición de orbitales atómicos parcialmente llenos, incluidos aquellos que no son el orbital s esférico.
Cuando se forma un solo enlace entre dos orbitales no esféricos, los dos orbitales tendrán una superposición cabeza a cabeza.
El tipo de enlace covalente formado por la superposición cabeza a cabeza de orbitales atómicos se denomina enlace sigma.
Los orbitales s y p que se superponen para formar enlaces covalentes no pueden producir las diversas formas moleculares en el modelo VSEPR. La teoría del enlace de valencia ayuda a explicar esta geometría molecular a través de la hibridación, o mezcla, de orbitales atómicos.
Algunos orbitales atómicos involucrados en el enlace se recombinan para formar nuevos orbitales cuyas formas son un híbrido de los originales. El número inicial de orbitales atómicos y el número de orbitales híbridos generados es siempre el mismo.
Los orbitales híbridos tienen una forma diferente a la de sus orbitales atómicos constituyentes, con un lóbulo que es significativamente más grande que el otro. Por lo tanto, la densidad de probabilidad de electrones está altamente concentrada en un lóbulo direccional, lo que conduce a una superposición más efectiva con los orbitales de otros átomos. Para mayor claridad, estos orbitales a menudo se muestran sin los lóbulos menores.
Por ejemplo, en el estado excitado del carbono, los orbitales s y tres p que contienen los cuatro electrones desapareados se someten a hibridación, produciendo cuatro orbitales híbridos s-p-tres equivalentes que ocupan los vértices de un tetraedro regular.
La mezcla de un orbital s y dos orbitales p en el estado excitado del carbono genera tres orbitales híbridos s-p-dos equivalentes con geometría plana trigonal.
De manera similar, la hibridación de un orbital s y un orbital p puede crear dos orbitales sp orientados a 180 grados entre sí. 
El concepto de hibridación también proporciona una explicación para la formación de múltiples enlaces. La superposición lateral de dos orbitales p da lugar a un enlace pi.
Sin embargo, un enlace pi solo se puede formar en enlaces dobles y triples cuando ya existe un enlace sigma entre dos átomos. Debido a que el enlace pi existe en lados opuestos del eje internuclear, los enlaces pi no pueden rotar alrededor de este eje.

teoría del enlace de valencia y orbitales híbridos

Valence Bond Theory and Hybridized Orbitals

Según la teoría del enlace de valencia, un enlace covalente se produce cuando: (1) un orbital de un átomo se superpone a un orbital de un segundo átomo, y (2) los electrones individuales de cada orbital se combinan para formar un par de electrones. La fuerza de un enlace covalente depende del grado de superposición de los orbitales involucrados. La superposición máxima es posible cuando los orbitales se superponen en una línea directa entre los dos núcleos.


 Un enlace σ (enlace simple en una estructura de Lewis) es un enlace covalente en el que la densidad electrónica se concentra en la región a lo largo del eje internuclear. Un enlace π es un enlace covalente que resulta de la superposición de dos orbitales p, uno al lado del otro. En un enlace π, las regiones de superposición orbital se encuentran en lados opuestos del eje internuclear, mientras que hay un nodo (un plano sin probabilidad de encontrar un electrón) a lo largo del eje. Todos los enlaces simples son enlaces σ, mientras que los enlaces múltiples constan de enlaces σ y π.


 Cuando los átomos están unidos en una molécula, las funciones de onda de los orbitales atómicos pueden combinarse para producir nuevas descripciones matemáticas que tienen diferentes formas. Este proceso se llama hibridación y se logra matemáticamente mediante la combinación lineal de orbitales atómicos. Los nuevos orbitales resultantes se denominan orbitales híbridos.


 Las formas y orientaciones de los orbitales híbridos, que se forman sólo en átomos unidos covalentemente, son diferentes de las de los orbitales atómicos en átomos aislados. El número de orbitales híbridos es igual al número de orbitales atómicos que se combinaron para generarlos. Todos los orbitales de un conjunto de orbitales híbridos son equivalentes en forma y energía, y su orientación la predice la teoría VSEPR. Los orbitales híbridos se superponen para formar enlaces σ, mientras que los orbitales no hibridados se superponen para formar enlaces π.


 Por ejemplo, en el estado excitado del carbono, los orbitales uno 2s y tres 2p se hibridan dando lugar a cuatro orbitales sp3 híbridos degenerados orientados tetraédricamente. En una molécula de metano, el orbital 1s de cada uno de los cuatro átomos de hidrógeno se superpone con uno de los cuatro orbitales sp3 del átomo de carbono para formar un enlace sigma (σ).


 De manera similar, la mezcla de un orbital 2s y dos de los orbitales 2p del carbono genera tres orbitales híbridos sp2 equivalentes con geometría plana trigonal, mientras que la hibridación de un orbital 2s y uno de los 2p crea dos orbitales sp orientados a 180° entre sí.


 Para los átomos que tienen orbitales d en sus subcapas de valencia, la hibridación de cinco orbitales atómicos de la capa de valencia (uno s, tres p y uno de los orbitales d) da cinco orbitales híbridos sp3d con geometría bipiramidal trigonal. Se obtiene una disposición octaédrica de seis orbitales híbridos mezclando seis orbitales atómicos de la capa de valencia (uno s, tres p y dos de los orbitales d), lo que produce seis orbitales híbridos sp3d2.

Teoría del enlace de valencia y orbitales híbridos

De acuerdo con la teoría del enlace de valencia, un enlace covalente se produce cuando: (1) un orbital en un átomo se superpone a un orbital en un segundo átomo, y (2) el único ...

valence-bond-theory-and-hybridized-orbitals

Education

Educación

JoVE Core

Organic Chemistry

Química Orgánica

Unit 1

Unidad 1

Covalent Bonding and Structure

Enlace covalente y estructura

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

covalent bond overlap and orbital hybridization

Covalent bonds form when orbitals on two atoms overlap and their single electrons pair up. The bond is stronger when the overlap is greater. Maximum overlap happens when the orbitals meet along a direct line between the two nuclei.

A sigma bond, or σ bond, is the kind of covalent bond found in a single bond in a Lewis structure. In a σ bond, electron density is concentrated along the internuclear axis. A pi bond, or π bond, forms when two p orbitals overlap side by side. In a π bond, the overlap lies on opposite sides of the internuclear axis, and a node with no electron probability lies along the axis. Single bonds are σ bonds, while multiple bonds include both σ and π bonds.

When atoms join in a molecule, atomic orbital wave functions can combine to make new orbital shapes. This process is called hybridization, and it is described by the linear combination of atomic orbitals. The new orbitals are called hybrid orbitals. They form only in covalently bonded atoms, and their shapes and orientations differ from those of atomic orbitals in isolated atoms. The number of hybrid orbitals matches the number of atomic orbitals used to make them. Orbitals in one hybrid set have the same shape and energy, and their directions follow VSEPR theory. Hybrid orbitals form σ bonds, while unhybridized orbitals form π bonds.

Carbon shows this pattern clearly. In its excited state, one 2s orbital and three 2p orbitals hybridize to form four equivalent sp3 orbitals arranged tetrahedrally. In methane, each hydrogen 1s orbital overlaps with one carbon sp3 orbital to make a σ bond. One 2s orbital and two 2p orbitals can also mix to make three equivalent sp2 orbitals with trigonal planar geometry. When one 2s orbital mixes with one 2p orbital, two sp orbitals form and point 180° apart.

Atoms with d orbitals in the valence shell can form larger hybrid sets. Mixing five valence shell atomic orbitals, one s, three p, and one d, gives five sp3d hybrid orbitals with trigonal bipyramidal geometry. Mixing six valence shell atomic orbitals, one s, three p, and two d, gives six sp3d2 hybrid orbitals with octahedral geometry.

Covalent Bond Overlap and Orbital Hybridization

covalent-bond-overlap-and-orbital-hybridization

what is organic chemistry?

Carbon Compounds in Everyday Life

Organic chemistry focuses on carbon compounds called organic compounds. These compounds may come from living things or be made by chemists. Carbon is the main element in them, and it bonds with other carbon atoms as well as hydrogen, oxygen, nitrogen, and sulfur. Carbon can form up to four strong bonds. That ability lets carbon atoms build chains and rings of many sizes, shapes, and levels of complexity. Not every carbon-containing substance is classified as organic. Carbonates, cyanides, and...

electronic structure of atoms

Atomic Orbitals and Quantum Numbers

Atomic orbitals and quantum numbers describe how electrons are arranged around the nucleus. An atom has a small, positively charged nucleus with electrons surrounding it. The nucleus contains protons and neutrons, and the quantum mechanical model gives a better picture of this structure than older models. Protons carry a +1 charge and have a mass of 1.0073 amu. Neutrons have no charge and have a mass of 1.0087 amu. Electrons carry a −1 charge and have a mass of 0.00055 amu. The number of...

electron configurations

How Electrons Fill Atomic Orbitals

Electron filling in atoms follows a set order based on orbital energy. The Aufbau principle says each new electron enters the lowest-energy subshell available. The Pauli exclusion principle says no two electrons can share the same set of four quantum numbers. Hund’s rule of maximum multiplicity says electrons stay unpaired in equal-energy orbitals when possible. The order of filling follows the relative energies of the subshells. A common sequence is 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, and so on.

chemical bonds

Chemical Bonds: Types and Strength

Chemical bonds help atoms reach a full valence shell like the nearest noble gas. The main bond types are ionic, covalent, and metallic. Bond energy and bond length also help explain how strong a bond is. An ionic bond forms from electrostatic attraction between cations and anions. In many cases, one atom transfers electrons to another atom, and the ions form from that transfer. Ionic bonds have no defined direction because the attraction spreads evenly through three-dimensional space. A...

polar covalent bonds

Electronegativity in Polar Covalent Bonds

Polar covalent bonds form when atoms share electrons unevenly. This happens in covalent bonds between atoms that have similar, but not identical, tendencies to attract electrons. Nonmetal atoms often make these bonds with other nonmetals. Hydrogen gas, H2, is a simple example of a covalent bond between two hydrogen atoms. A covalent bond begins when two atoms move close enough for their valence orbitals to overlap. In hydrogen, the 1s orbitals overlap and the single electrons on each atom...

lewis structures and formal charges

Lewis Structures, Bonds, and Formal Charge

Lewis structures show how atoms share electrons in covalent bonds and in polyatomic ions. Lewis symbols help draw these structures, and the periodic table helps predict how many valence electrons an atom has and how many bonds it can form to reach an octet. Group 18 elements, such as argon and helium, already have filled electron configurations. They rarely take part in chemical bonding. Atoms in group 17, such as bromine and iodine, need one more electron to reach an octet, so they can form...

vsepr theory

Molecular Shapes from Electron Pairs

Molecular shape can be predicted from the way electron pairs arrange around a central atom. Valence shell electron-pair repulsion theory, or VSEPR theory, uses a Lewis structure to count bonding pairs and lone electron pairs. The main idea is simple: electron pairs spread out as far as possible to reduce repulsion. In a molecule, the valence electrons around the central atom can be bonding pairs or lone pairs. Bonding pairs are found mainly between bonded atoms. Lone pairs stay on one atom and...

molecular geometry and dipole moments

Predicting Shape and Molecular Polarity

Molecular shape and molecular polarity can be predicted with VSEPR theory and dipole moments. Start by writing the Lewis structure of the molecule or polyatomic ion. Then count the electron groups around the central atom. Lone pairs and bonds both count as electron groups, and a single, double, or triple bond each counts as one region of electron density. Use that count to identify the electron-pair geometry. Next, use the number of lone pairs to determine the molecular structure. If more than...

resonance and hybrid structures

Resonance in Nitrite and Carbonate Ions

Resonance explains why some Lewis structures do not match the measured properties of a molecule or ion. When two or more Lewis structures have the same atom arrangement, the real electron distribution is an average of the structures shown. The nitrite anion, NO2−, is one example. It can be drawn in two ways, with the N–O and N=O bonds in different places. If nitrite had one single bond and one double bond, the two bond lengths should be different, because a double bond is shorter and stronger...

valence bond theory and hybridized orbitals

Covalent bonds form when orbitals on two atoms overlap and their single electrons pair up. The bond is stronger when the overlap is greater. Maximum overlap happens when the orbitals meet along a direct line between the two nuclei. A sigma bond, or σ bond, is the kind of covalent bond found in a single bond in a Lewis structure. In a σ bond, electron density is concentrated along the internuclear axis. A pi bond, or π bond, forms when two p orbitals overlap side by side. In a π bond, the...

mo theory and covalent bonding

Bond Order and Molecular Orbitals

Molecular orbital theory explains how electrons are arranged in molecules. It treats electron regions in a molecule much like atomic orbitals in an atom. A molecular orbital is the region of space where a valence electron is most likely to be found. Molecular orbitals form through the linear combination of atomic orbitals, or LCAO. When atomic wave functions combine in phase, they create regions with high electron density. When they combine out of phase, they create nodes, or regions with no...

intermolecular forces and physical properties

intermolecular-forces-and-physical-properties

How Intermolecular Forces Affect Matter

Intermolecular forces are the attractions between molecules, and they help explain how matter behaves. These forces influence melting points, boiling points, and whether substances mix with one another. Water has a much higher boiling point than hexane, which shows that water has stronger intermolecular forces. Three main kinds of intermolecular interactions are covered here. They include ion-dipole forces, dipole-dipole interactions, and van der Waals forces, which include London dispersion...

solubility

Why Some Substances Dissolve in Water

Solution formation depends on how solutes and solvents interact. A solution is a homogeneous mixture made of a solvent, which is the larger part, and a solute, which is the smaller part. The physical state of a solution is usually the same as the solvent. Concentration is often described as dilute for a low amount of solute or concentrated for a high amount of solute. When a solute dissolves, its particles are surrounded by solvent species. This process is called solvation. If water is the...

introduction to functional groups

Functional Groups and Organic Molecules

Functional groups are groups of atoms with specific chemical properties that appear within organic molecules. They are sometimes shown as "R." These groups sit along the carbon backbone of macromolecules, which can form chains or rings of carbon atoms. Functional groups help functionalize a compound. That means they can give the molecule different physical and chemical properties. In organic chemistry, this change in group structure can strongly affect how a compound behaves. Common...

overview of advanced functional groups

Advanced Functional Groups in Organic Chemistry

Advanced functional groups are atom clusters in organic molecules that give those molecules specific chemical properties. They are sometimes shown as "R" in formulas. By changing the atoms attached to a carbon skeleton, a functional group can make a compound behave differently in physical and chemical reactions. This topic covers several major classes of organic compounds with advanced functional groups. Aromatic hydrocarbons include benzene. Phenol is another example and is also called...

key terms and concepts

Learn how orbital overlap forms sigma and pi bonds, then see how hybridization creates sp3, sp2, sp, sp3d, and sp3d2 orbitals in molecules.

Covalent Bond Overlap and Orbital Hybridization | JoVE K12

organic chemistry

JoVE Core Química Orgánica explica los conceptos básicos de la estereoquímica, las reacciones y sus mecanismos mediante lecciones de vídeo animadas, concisas y fáciles de entender. Además, los vídeos de científicos en acción muestran la aplicación de esos conceptos en experimentos de investigación clásicos y originales, desarrollados actualmente en laboratorios de todo el mundo.

Covalent Bond Overlap and Orbital Hybridization

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